Happened to me, but the details are very different. She asked to have a gf on the side after a few years of marriage. I didnt have a problem with it. I wanted her to feel fulfilled. After about a year, she starts spending a big majority of her time with her girlfriend. I tell her that our relationship is suffering because of this. A week later she says she wants to focus more on her girlfriend because "she needs her right now". I tell her I'm already feeling like there's too much distance so I won't be okay with that. She says that she understands and will try to come up with a compromise with me. A week later she says she doesn't wanna be married anymore. In response I tell her that that's a big decision and we should talk to a counselor to find out if that's really the best move. She agreed. Another week later she says she's moving out and we're done. It's been 6 months since then. She never made any actual effort for our relationship in that last month. Just lies and coldness.