Been having overwhelming urges to check my wife's phone since she recently came home after an affair. We have three kids, and are trying to save the marriage. She says she has ended the relationship, but clearly I cannot believe much of what she says. Tonight she caught me red handed, and I felt so ashamed. She let me know how she feel, without blowing up, which is very new to me, she normally would lose it over something like this. She said that if she wanted to be with him, she would be with him, and there is nothing I can do about it, which is true. I apologized and said I couldn't help it, and that it's hard to trust her. Usually she would completely change her attitude, and avoid me, be rude to me, after an event of this type. But tonight she quickly composed herself and just said her peace, then went on as normal, which is completely throwing me for a loop. I want to save this 12 year marriage desperately, and know I have no blame for the affair, but the point at which our marriage is at, is 50/50. I am confident the shame I felt will keep me from doing this again, but would like insight on other mistakes I might make, and tips for healing and building trust going forward. Fwiw, I'm also a Christian.

TL:DR Wife cheated, can't stop snooping, got caught, don't want to push her away further after she came back home. Family of 5. Help!