No, it isn't wrong. Your marriage is a contract between the two of you, not between the two of you and God. If you wish to change the terms of that contract by mutual agreement, then that's between the two of you. You don't need the rubber stamp of a notional bloke with a halo to enable you to do this.

I was in a similar situation with my ex. We had a non-religious ceremony (in a castle, it was very nice) and, years into the marriage, decided on a sexually open relationship and to begin dabbling with the swinging and BDSM scenes. The number of people who were massively upset about our "breaking our wedding vows" was surprising. Even more surprising was seeing it come from non-religious types. We'd written our own vows. I don't recall exactly what they were, but she wasn't the 'honour and obey' type. I don't think any of them precluded a sexually open relationship.

The trouble is that people project their insecurities onto others with open relationships. They like the rule that "Once you've paired off, your partner is the only person you have sexual thoughts about, ever." Anything that deviates from that level of exclusivity makes them uncomfortable. I think a lot of it stems from not feeling that they're worthy of their partner, and that they are likely to stray given an opportunity.

That said, it takes a strong relationship to survive a sexually open dynamic. It turned out ours wasn't. That's why she's now my ex.

No it's not

Whatever floats your boat. If you are happy in your decision, why worry about other's opinions?

Absolutely not wrong. If it's something you both enjoy, it enhances your reationship then to hell with restrictive cultural norms.

We deny ourselves so much based on what other people think, what society expects of us or the effects of our upbringing. There is so many hangups about and sexuality.

Happiness should not be conditional on the opinions of others. Enjoy yourselves and take care of each other.

That's an odd question to me.

You made a joint decision for your marriage and relationship. You seem content.

Who is the arbiter of whether it is wrong, but the two of you?

In my opinion, grown adults can do as they please, within reason and within the confounds of their relationships, and it's not for anybody else to judge.

It's not what I would choose for me, but rock on @flettie!

It is absolutely up to the parties involved to define what marriage is for them. The important thing is that you are on the same page with it and Honesty, compassion, and reliable communication are foundational factors.

I can't do it, and it makes me a little jealous that you can. LOL, that being said, if its consensual with all parties nobody else's opinion matters! Have fun and enjoy!

It is your life, your collective freedom to do as you must and please and nobody should be a critic at all! I Salute you guys for being Honest with each other beyond the norm.