What is going on with me.?

I feel so hot an cold every day. Married 15 years 3 kids. Separated for 8 month with wife. I have completely lost all my feelings for her. She is a great mother. When I see her around my kids I am thankful I have this woman mother my kids. She is a stay at home mom, but I think bases on my previous postings and peoples comments that I spoiled her to a point that she became controlling and put me down in front of other and I retaliated by separating from her. But I am hot and cold. Some days I hate her so much that I can't even bear to look at her. Other days I am fine with her. Not great but ok. I was seeing someone else while separated and man the feelings I have for her are unreal. Rebound? maybe. But I never felt like that about my wife before. I love being with her spending time with her. She has a child of her own( single mom) and I can be on the phone with her for ours. is great also. But I wonder what made me so bitter toward her.