How very appropriate to find this now.
We have a close friend who's marriage was exactly one more CPR repetition away from declaring the ToD. We didn't know her husband at all, just her and her issues with him and the relationship.
We watched her cheat briefly.
We talked to her a LOT. We chided her about having issues she hadn't discussed with him, how it was unfair to think those things and decide in advance he wouldn't work with her.
Out of the blue, literally overnight, they're working on things. She had a "WTF why not" moment, and spilled it all out, unfiltered, unedited, brutally. She did it to push him away for good, to get it over with. Surprise - he reacted with concern, understanding, and willingness to work with her.
Within 24 hours, they're talking to us about a swinging situation (she is VERY attracted to Violet and Lana, and to me as well to perhaps a lesser degree, and we ALL bit our tongues for months when she talked about how unfulfilling her sex life was 'cuz we're all attracted to her, lol) and us helping them understand and ease into BDSM.
Now we're trying to help them fix things and look into non monogamy, celebrating their new understanding and willingness to work on the relationship - and trying to help them understand that ORE and new understanding doesn't mean suddenly jumping into Poly or swinging overnight because you're both "okay with it". Which is more difficult than I'd like to admit 'cuz the mutual attraction factor is sky high, lol. Still, if we're going to play together, we want to be a continued source of positivity - not a catalyst to disaster.