I just don't understand!

How can anyone who says to me "I love you more!" Hurt me so bad? I am trying to research about why and how but I still just can't wrap my head around it. I miss who he was, a very wonderful man. I wish he could be that guy again. I loved him so much and even though I really do feel hate for all he has done I still have love for him. I know how good of a person he can be. Why did he have to be so cruel, abusive and mean in the past 4 years?? Wondering and wishing is driving me nuts and not productive but I obsess when I need to know why. I can't help it. 
I do know with untreated adhd they tend to get a rush out of fighting with their SO. They need that adrenaline rush, hence why they also tend to be impulsive. Reason why he has cheated on me also. But I'm definitely not putting all blame on his adhd, he could have found counseling, meds, behavior therapy and whatever else to help save our marriage. I actually did one last attempt last week to try to salvage our marriage. I told him he can seek help for his adhd and told him how happy he would be and how he could enjoy life but he refused. I was going to tell him that I would also seek counseling to help with my scars of all that he has done to me. Then after awhile of individual we could go to marriage counseling. he has refused my plan, no compromise on his end, no input, nothing. He just outright refused. 
Many times I have put in the effort to try to fix us because I believe marriage really is a lifelong commitment. But it's impossible to love someone who doesn't love me back. He may say it but his actions contradict his words of love. I want him so badly to bring my 7 yr old back to me, I need to make sure she's ok and that I can hug her and cuddle her and tell her it'll all be ok. She's my world and he is ripping her away from me for no reason whatsoever, just to get me back. I just don't get it. I would never ever do this to him unless he was abusing her. I just don understand how someone who states they love me Can be so abusive and cruel and use our daughter to get back at me.