This entire friendship was a facade.

I apologize for jumping into Reddit for the first time, but I genuinely need an outside perspective on how to handle a tricky situation. For some context, my boyfriend and I met another couple—I'll refer to the woman as M and her partner as K—at my daughter’s school two years ago, and we’ve become good friends. Our kids also get along well. However, M has made some remarks about K that always seemed off, and there were random stories that just didn't add up. Wanting to give our new friendship time to develop, I held off on forming any judgments. Fast forward to this past weekend when M and K came over for drinks. M ended up getting quite drunk and asked me to call her a cab, but since I had only had one drink, I offered to drive her home instead. K stayed behind to hang out with my boyfriend, which was fine. While driving M home, she started getting sassy, questioning why I was taking her home and insinuating that no one wanted to hang out with her. I reminded her that she was the one who asked to leave and suggested she get some rest, offering to pick her up if she wanted to come back later. When I returned home, the guys were chatting, and I decided to spend some time on my computer before starting dinner. That's when K opened up about his tumultuous relationship with M. He shared some hefty claims: she has cheated on him, been physically abusive, struggles with alcoholism, and fails to contribute to their household. Everything I had ever questioned about M suddenly made sense, confirming all my doubts and the odd comments she had made in the past. You might wonder how I could trust K’s story, but there are times you just know. My boyfriend completely believes him as well. The pain and defeat in K’s eyes were palpable, and he also acknowledged his own faults within the relationship, which made me feel he was being honest. He stays with M mainly out of concern for their child and fears of losing custody if things escalate. After dropping K off, M showed up at my place, visibly upset and still drunk. I asked her to leave and told her I needed to process everything before talking again because I was overwhelmed. M then began texting me furiously, saying things like, “I hate when he does this,” and “he lies, remember?” I didn’t respond at first but eventually told her that I needed space to think about the situation. With our kids attending the same school, I’m uncertain about the future of our friendship. M hasn’t even apologized for showing up at my door unannounced, which I’ve made clear is not okay. It’s obvious she needs help, but I’m unsure how to proceed. I've spent the weekend weighing my options, and I'm really lost. K doesn’t want to lose our friendship either, but I’m at a crossroads and need some guidance. Ignoring M feels wrong, but I’m unsure how to move forward from here. Any advice would be appreciated.