is it wrong of me??

Is it wrong for me to expect some kind of reaction when I send my boyfriend nudes? Anytime I send him something I think is sexy his responses are so monotonous, today he literally just said "thanks" and changed the subject. It's a complete self confidence killer. Whenever he sends something I hype him up and make him feel good, I just want some reciprocation. What's worse is that after he noticed I was a little upset about it he went and tweeted "I can't contain my enthusiasm for ass and titties". I don't really know how I should take that or what his intention with it was, I may have taken it the wrong way but it seemed hurtful. He's like this about other things in our relationship and lately it's been making me feel really insecure and just tired of being with him.