Don't know what to do

Dear anonymous,

My wife and I are working on our marriage. We hit below rock bottom and almost had a divorce. I was dumb and stupid and never cared about anything, but I recently turned a new leaf. Needless to say, I was too late and she lost all feelings for me. We decided on a break with terms of not sleeping with anyone, but after going through her phone last month, I found out that she's slept with a Co-worker and her best friend. I confronted her and she did get defensive about it. We have tried to come to terms with her wanting to hang out with her best friend again, but she doesn't want to make me torment myself as I'd constantly think they'd be doing more than hanging out. She's torn between me and him and though I love her, I don't know what to tell her. Should I just suck it up and let her hang out with him? It just sucks because we have 3 kids and I don't want to lose her...