She cheated and i took her back and was lovey dovey for a few days but now i feel the opposite, why? Is normal?

I wanted her back and she claims she made a bad mistake and still wants me so i took her back. I wanted to take her back right after i found out but i knew it was best to wait at least a week so she could feel some kind of hurt and see what she was missin. Well i took her back and for a few days we were all over each other but then out of no where it just hit me "what am i doing here" like i dont wanna be around her now or anything like everything she does jus annoys me hardcore. I also feel like she can **** somebody else right in front of me and i wouldnt care. Most people would be feeling and thinking when is she gonna do this again but with me its i dont even care... Is this normal or will it pass cause i dont wanna tell her its definitely over if im gonna feel different next week. And just to further let you know the situation we have 3 kids (i adopted her oldest) 2 are mine and have been together for almost 5 years now