Lol yeah, you lack empathy apparently. i'm polyamorous, i don't intend to be in a monogamous relationship. but that doesn't mean i wouldn't understand someone feeling upset over being cheated on. if i fell in love with a monogamous person and decided to be with them, knowing their feelings and agreeing to certain rules for our relationship, i would be an asshole to break those rules. don't want to be in a monogamous relationship? break up. lying to your partner about something they consider important is a shitty thing to do.

Nope - even when I was of childbearing age - this was not my bag.

Be with someone or don't be with someone. Hearts get broken by cheating on them.

You want a flexible relationship? State it at the onset. "Open Relationship" or "Poly".

It's very different from a monogamous marriage and those of us who prefer monogamy don't want that in our lives.

We have a right to our expectations as you have a right to your flexibility.
Just be grown ups about it. Tell each other.

My first long term relationship was great for the first 10 years, the next 3 were a bit rocky but still good the last 2 were lots of silent treatment. I suspect he did some foolin' around, I did not.
Seems one of two things primarily screw up a relationship - money or sex. Sometimes it's all one but in my case we had great sex but he did not like being fiscally responsible and I was trying to work towards the future. Thank goodness I did not officially marry him, I'd of lost big time.

My wife of 32 years and I had an agreement that if either one of us screwed around, we wouldn't tell the other, as long as it was just sexual and not romantic. We split as friends after the kids were grown because we were going in different directions. I did drunkenly fool around a few times, but I didn't tell her, and I have no idea if she did or not, and it doesn't really matter.