My friend is cheating but doesn't want to tell her husband it's the reason she wants to break up
My best friend of 18 years, recently came to me and said she was going to leave her partner of 12 years (married for 6 months). Reason she gave was that he wasn't supportive, didn't pull his weight around the house, games too much and she's generally just fallen out of love with him.
I obviously asked if she'd spoken to him which she said she had and had given him a couple weeks to do better. After this 2 weeks she said she was done. He had done better but the feelings weren't coming back.
I accepted this and said I'd always support her, she can't help her feelings but also mentioned that 2 weeks wasn't really long enough to make a decision but I trusted her judgement.
That day she gets on a flight and moves back in with her parents. She asks me round to chat so naturally I ran round as quick as I could with wine and tissues and was ready to give all the hugs she needed. I hadn't seen her since the wedding as she and her husband live in a different state.
What she then told me was that she had been cheating on him for the best part of 2 years and that was the real reason she had broken up with him.
When she sat her husband down and told him she was leaving, she didn't tell him she was cheating or that there was someone else because "it would break him" so just said all the bs reasons above.
When she was talking to me, she was being very cold towards her husband and didn't seem to care when I said he needs to know about the cheating, or he'll spend the rest of his life wondering what the hell went wrong. She also disregarded his feelings by saying "I'm done, there's no point in talking it through more". For him this came out of left field and he's reeling!
I also mentioned that I was hurt by all of this as I'd spent weeks consoling her and being supportive but in actual fact she was playing the victim. I've known her since we were kids and were more like sisters (or so I thought). I love her husband too, he's a genuinely nice guy that will do anything for anyone. Thought they were a match made in heaven and I've known him since day 1. I feel like I've been lied to as well both over the last 2 years and for the past few weeks.
The wedding was just 6 months ago but the affair has been going on for over 2 years! No idea why she didn't call it off! She said she got swept up in it. It was a destination wedding so we each spend thousands of dollars to attend, took extended PTO and spent countless hours helping her plan the smallest details. When I say there were no signs, there were literally no signs.
I'm just baffled, heartbroken and disappointed in my friend. I thought I knew her better than I know myself but clearly she's not that person.
I'm angry that she doesn't want to tell her husband she's cheating. It's going to get out (3 other friends now know the full story) so surely he'd rather hear it from her. I was urging her to tell him but she won't.
I'm wondering if I take it upon myself to tell her husband myself? Feel it's not my place but that he needs to know or it'll ruin the rest of his life.
I'm also not convinced she's not having some sort of mental breakdown as I've never seen her this emotionless in my whole 18 years of knowing her. She must doesn't seem to care what she's doing to him.
What should I do here?