My daughters (18, 16) are mad at me because I won’t tell them the real reason why I divorced their dad (both divorced in our 50s)

I divorced my ex-husband 8 months ago after 22 years of marriage. We all live in the same home but different levels - I live on the bottom, he lives in the middle, and the girls live on the top. It wasn’t like that before of course but it worked for everyone and it actually felt like having a new home without actually having a new home. We took the stairs to get to each other’s floors.<br><br>My youngest daughter (16) is in high school and doesn’t drive. The eldest (18) drives. She’s in college but is staying home this year and next before moving away. Anyway. <br><br>Their dad cheated on me years ago. I forgave him and he promised to never do it again. Well, he did it again recently. I’m in my 50s and decided I didn’t want to deal with the hurt. So I left him.<br><br>The girls know I left him but I haven’t told them why yet. I don’t want to ruin their image of him. Honestly I feel guilty that I didn’t leave him the first time. <br><br>Both of them have been upset about the arrangement and have been begging me to tell them why. They have figured out that their dad did something wrong but I haven’t confirmed it yet. I haven’t told anyone why, not even my family, except for my best friend. <br><br>They’ve recently started acting out. The youngest is mad at me for making them move or something (we all stayed in the same house) and the oldest is pissed off at me for not telling her why their dad and i broke up. I don’t know what to do. I just want to protect them from seeing him as a bad person but at this point I think I’m over protecting them. What do I do?<br><br>tl;dr! my ex-husband cheated twice and I won’t tell the real reason why i divorced him to my children. they’re angry and I don’t know what to do