Hi everyone.

Posting here as I'm new to this issue and would like some insight. 

I am dating a guy for the past 10 months. He was with a girl who was extremely abusive emotionally, cheated and manipulated him, messed with his head, was a great actress, lied, made him basically beg and crawl for truth on certain matters, made up false stories to belittle him, laughed in his face and called him psychopath etc. 
she's got the typical traits of a sociopath, according to the way he describes her. Their relationship was very intense and very exciting apparently.

He broke up with her long time before we started going out, and I have fallen for him massively as he is a lovely person. However it seems he has a hard time developing 'strong' feelings for me due to what he has been through. He has feelings for me but not strong ones. He says this is due to his past relationship, as it still bothers him. He does not have feelings for his ex however he feels horribly treated and that it was unjust as she belittled him and he did not do anything back other than block her and never speak to her. 

I do like him a lot and I would want this relationship to go develop. Are these sorts of feelings he has something that's an effect of EA? That you have a difficult time feeling strongly for someone else? I am nothing like his ex in any way. 

Thanks a lot everyone.