Actually, I think it's a waste of time discussing whether it fits perfectly rape's definition. What really matters is that he's having sex with you even when you don't feel like it, and this is VERY bad,... It should never happen, and should never be tolerated. But of course you know that, since you say it yourself, so that's also not the issue.
The issue is why are you spending time with a person that does not respect you? Why not breaking up with him, and find someone who you can be happy with? Are you scared of being single for a while?
It's common for women who suffer from affective dependence to endure anything just so that they are not alone (beaten, raped, humiliated, etc). They must seek help and counselling, just like a depressed person should get help before things go out of hand. Because you don't seem to be able to do it on yourself, I think you should really pick up the phone and get a meeting with someone who can give you professional help.