How do I not let my boyfriend turning me down sexually bother me?

I have been “with” my boyfriend for over a year but only physically together for 6 months. He was long distance so we moved in together. He is my best friend as well as my lover. In all other areas I am very happy in our relationship. However, he sometimes turns me down sexually. I can understand if he is having a bad day or something, but there seems to be a pattern to when he does. And he doesn’t flat out turn me down, but leads me on a bit.

Now, it’s not that I think he’s purposely trying to be mean. I think it’s that he finds it hard to upset people. But I digress. Usually we are intimate like every other day, but sometimes it’s more frequently. And sometimes if I am not able to have normal intercourse, or reach orgasm, I will just pleasure him by other means. So, he’s gotten his satisfaction for days straight and then I will want a release. When this happens I try and initiate or flat out tell him I want sex (or both.) He will then say yes, or act like we will… But then he ends up making excuses or not following through. This upsets me for 2 reasons. 1: It’s sort of emotionally confusing.(I’d rather him just tell me flat out he’s not in the mood, then I don’t continue to try or get my hopes up.) 2: It seems that he’s only turning me down when he’s had his fill and isn’t really thinking about me, when I try and take care of him and please him.

I have spoken with him about this issue. He seems to care that I am upset and say that he’s going to be better. But this same thing has happened I would say 4 times (which may not seem like that much, but keep in mind we’ve only physically been together for 6 months and it always happens pretty much the same way.) So I can’t help but feel insecure, but mostly I just wonder if this will be something that will continue or get worse? And I also can’t help but think that he’s being a little selfish. People aren’t always “in the mood,” but we do things because we care about the other person…What do you all think about this?