I've now had two long-term relationships go up in flames due to practicing ENM - a 4-year relationship, and a 12-year relationship (essentially my marriage). In both cases, my partner refused to follow any agreed-upon boundaries, lied to me, and hid all encounters with the opposite sex. Both used it essentially to cheat on me.

The 12-year relationship just fully ended a couple months ago, and I'm starting to think about what I want in the future. I'm a very sexual person, and consider myself very open and a good communicator. I'd love to not shut the door on all forms of non-monogamy. But... it's hard to not do that, in my position.

In future relationships, I'm starting to think that I might only be okay with physical activity with someone else if I'm present, or vice-versa - essentially swinging. It's what turns me on the most anyway (sharing that excitement and novelty with my partner), and it's the only way I can think of in which something couldn't be hidden from me where the partner pretends to be playing by our rules. It's more clear-cut than ENM or poly.

Experienced swingers, how do you feel about this? I know the danger is still there - what if she sleeps with another guy with me, and then all of a sudden that opens a door in her mind, etc etc. I'm afraid monogamy is the only path for me, even though I've proven to be fully capable myself of honoring all agreements and navigating ENM. Hoping that's not the case. Any thoughts that come from a place of experience and kindness are appreciated.