What do I do now? Let it go?

A few weeks ago I got a shady text from my ex-boyfriend, whom I've remained friends with for the last year and a half (we broke up in August 2012). I asked him if he was in town (he lives 45 minutes away) and if he wanted to go grab a drink. He said that he wasn't and that he didn't want to spend any more time or money on our "fake dates." (I guess he thinks we flirt even though I am in a serious relationship with someone else.)

It was surprising because even though we weren't especially close as friends, he told me to think of him as a friend first and an ex second. So what gives about his new change of heart? What do I do now? Just let it go and not talk to him? I haven't talked to him since he said that.

He may be hurt because whenever I'm in his hometown and we go out, I crash on his living room couch if I've been drinking but won't hook up/date him now that I'm in a relationship. (My boyfriend knows that I've stayed there.)