I say better not to lie, but that's mainly the Asperger's speaking I think. Like other people said, do what you can live with. But be careful of getting accidentally exposed, too. If you get any good idea of your mom being ok with it, you should probably tell her. There's likely no way around a lack of belief with the Boy Scouts, though.
Question: If you don't believe, and you're using 'a' in front of it, why are you capitalizing god?

I live one... what can I say? I have lived one almost all my life.

If telling your mother would make her feel bad, I would just enjoy the time that you spend with her since no one is getting hurt. I pretended to believe in god for my mom. She passed away this year.

If it wasn't for your mom, I'd say join a Unitarian Universalist congregation. Otherwise, don't sweat it, lots of people go along to get along.

Be true to thine own self. If not the stress of living the lie will wear you down. Your friends and family will love you no matter.

Are you willing to live with the consequences of your actions? If you tell your Mama what is that going to do to her? If you continue living a lie what is that going to do to you? Mama might be OK with it because she loves you, but then again... If you have to give up scouting what will it do to you? If you continue to lead the scouts while not believing what will that do to you? If you come out what will that do to your position in the community? Tough position, good luck with figuring it out.

if you are helping people and don't mind the church bit and help your mum I can't see the problem. I love my dogs but there are things that fall out of them in the garden I don't like but its well worth it.

No big deal. They are the ones living a lie. Everyone is welcomed in the Church at whatever level of belief. The one thing I like about the Church is the community. Be in the community and throw in an odd ball question once in awhile, let them peek into what is not Christian. If asked, don't lie... say the truth, I don't believe Jesus is the son of God. They can't judge you, because part of it is that they are not that firm on their beliefs. I would continue to do it, if it comforts my mother.

I would not live as you do, but I am not you. I will not judge you.

Some people have no trouble living a lie for the sake of the people, or activities, they love. Some people can't do that. You're the only one who can decide which is right for you.
All that matters is what YOU can live with.

It's only living a lie if you assume other people truly believe the doctrines. Basically, a church is a social club. Beliefs are tangential, at best. No need to really be too hard on yourself. If you're happy doing the scout thing and enjoy the company of the people of your church, don't sweat it. You gave your justification when you said: "be around people you care I care about and participate in the organization I love." That's what really matters. You'd be surprised at the number of pastors who really don't believe what they preach. They do it because it's what they are paid to do and it's the only option they have available for supporting their family. They maintain appearances. I've been there, I know.

Sometimes in life there is no right or wrong answer, this question being the case. It is a no win situation because both have their bad results. The only thing you can do is make your own personal judgment and do what feels personally right for you. You may know your answer quickly, or it may take a while. There is no easy solution unfortunately. In a random similar situation, people who defect North Korea do get their freedom but their families are probably executed. There’s no right answer in that case either. I personally am an Eagle Scout and have been in the BSA for 6 years. I grew up Mormon and did both extensively. I am an Eagle Scout but I ended up as an agnostic growing up, and I am happy with my boyscout years, but it’s not nessesary for my life, just an added bonus. Being an Eagle Scout for me is something cool to have rather than something for me to self validate my own importance as an individual. If your quality of life is dying and it is killing you on the inside to pretend to be religious for the sake of scouting, I’d say move on. Don’t love something that doesn’t love you back.

I’m aware of the multitude of opportunities I’ve had to become involved with various church oriented social activities. But didn’t. Some I felt compelled to explain myself, ‘you wouldn't want me,’ ‘my lack of a belief in a god would make me a hypocrite,’ ‘so I can’t belong.’ I walked away, and they understood.

You stayed… it’s of course up to you how you remedy that, or not. Seems to me, if honestly truly is a priority, it may become the best policy. It actually hurts to say this, but I’ve long ..forever considered your kind as the worst… Those continuing to prop up an ultimately hostile concept that would so quickly come down on me.

Perhaps you’re paying a price. At least I’ve raised children, supervised them, taught them, and presented someone they could trust and safely admire. I hope you can do the same.

I say do what feels best. If you don't want to sacrifice relationships based on your beliefs you're already better than many theists. At the same time it's on you to be honest with yourself. If you feel yourself going through the motions, as if acting out a play, it's going to potentially turn to apathy for things you do enjoy. My biggest suggestion is, if you decide to come out, ease out of your positions first. A scoutmaster and active church member suddenly dropping everything due to atheism is naturally going to shock people. Holy Koolaid is the best start for resources on coming out. Check out his youtube channel and the pages he talks about. Don't hurt yourself by jumping the gun and remember no sacrilege is committed if you truly feel that your silence about your beliefs is a minor payment in comparison to being apart of the communities you enjoy.

You're not doing anything wrong.

Do what feels right to you.

Seriously - get a life.

Forgive yourself. Most of us are living a lie, one way or another.

More like you're living a reality that makes other people happy and now you're beginning to question this stage in your life, which is a positive thing for you if you can act on it and live your truth with or without God

I don't think that would be for someone else to say. HOw do you feel in your day to day life about it?

An organization that is too bigoted to accept you for who you really are does not deserve to have you. The same applies to relatives and friends.

Your morals and principles are your own. Without harming anybody you can do and be what ever you want. Enjoy life and let no one know who you really are.

You are not saying which god you believe in. It doesn't have to be their god. The irony of a god creating is that you can create your own. Spiritual life is baked into our being as humans. But such a life is highly personal. Work on your own beliefs while joining in on the opportunity to learn from others around you. Your mom is happy you're going to church. She doesn't have to know why! Part your god concert is making others happy and sharing in their joy. Leading in your community and helping others grow into happy, healthy and responsible adulthood can be another tenant of year spiritual canon. Hope this helps. Helping folks sort these things out is a part of my higher power that leads me in its own way which is also my path to tread.

I attended church for a while to please my grandparents. I said the words and ate the cracker and sang the songs. (I kind of like some of the songs.) But my internal experience was always "I'm doing this for them." I never believed that what all those well-groomed people around me were talking and singing about was anything but rehashed Bronze age mythology.

But it made my grandparents happy and that meant a lot to me, much more than the inconvenience of going to church once a week for an hour and a half or so. My grandfather is now dead and I live far away from my grandmother and she is sadly losing her mental powers so I don't need to pretend anymore, so that's a relief. But I didn't think I was lying to them, I think they cared that I went to church because to them, that's just what you do, and they didn't trouble themselves with what I believed.

So you're not alone in this.

Sounds like it. That sounds fairly uncomfortable at times. Likely, it is becoming increasingly more uncomfortable as your inner truth seeks the light of outer expression. However, I wouldn't say you're living a "total" lie. You don't seem to be lying to yourself, at least.