Weird partners?

So, imagine you're getting to the nasty with your partner. They do something for you, and you go to return the favor, and they refuse. They tell you it's unimportant to them and that you don't have to do anything. Over time, they finally let you do things, but don't let you finish them off. It's not that they don't want to, or don't want you to, it's just not important to them.
​The problem with it is that it kills your self esteem. You love seeing them happy, and knowing you satisfied them. :/ You also feel as if they don't find you sexually appealing, though they say they do. 
​You talk to them about it and they just kinda brush it off and remind you it's not important. 
​What would you do? It's actually hurting the relationship.