People who are in the wrong (especially when confronted with cheating) often try to redirect the conversation and place the blame on you. Do not fall for this. The reason for her cheating is because she wanted to cheat. If you were the perfect boyfriend and gave her all the attention in the world, she would have cheated and told you that it was your fault for not allowing her enough independence. If you found a perfect balance there, she would have cheated and told you that it was your fault because you didn't make her toast dark enough. See what I am trying to say? She will always find a "reason" for her cheating and a way to blame it on you. But all of those reasons are just as lame as the toast reason.
Basically, your relationship will only work if BOTH of you want it to work. She begged you to come back saying she wanted to make it work, but a week later was cheating again? Doesn't sound like she wants it to work.
I understand your dilemna about your child, but it would be better for your child to spend time independently with one parent at a time who loves them than watch both of his/her parents continue to suffer through a disasterous relationship.
Good luck.
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