husband not asking for sex

Kristin
My husband is 40 and I am 29. We have a 2 year old daughter. He has many back issues which causes him a lot of pain and of course with that frustration and grumpiness because he hurts and can't take anything heavy duty for his pain
I am always the one to more or less initiate sex. He is shy as he doesn't become forward unless he drinks. Basically many past relationships screwed him up emotionally. I love him but I feel unloved since he isn't initiating things. Makes me feel like he doesn't enjoy sex with me 
I have talked to him prior about him being more open and forward. He says it takes two. Well yeah I get that and I do my part but I just don't know what else I can do. I mean if I ask him he will probably get embarrassed with a bit of frustration or anger that might rise to for me thinking that. I am just wondering what others think since I don't know who else to ask