well my ex-guy would only invite me over when he was bored.
and it turned out yes, he was using me.
Not that he didn't like me (or your guy doesn't like you) but it's possible he has a different idea of your relationship than you do. Do you want to date? do you want a relationship? or are you in this for FWB?
You have to make your choice very clear to him.
If he's willing to date, (or you guys already are dating), than he should be MAKING time for you, not fitting you into his schedule whenever he has nothing else to do.
Being used is not fun, especially when they own up to it and you have to split up.
Just make sure you and your guy are on the same wave length, and if you aren't, then you should be the one ending it (if he's using you) because ti's not healthy to be in a one-way relationship where you think the world of him and he only likes you for FWB.
I know It's hard to ask this kind of question to him at first because you know you might get the answer you're dreading (that he doesn't like you as much as you like him), but even so, you'll get over him eventually and find someone who appreciates you and works for your relationship and you'll be a MILLION times happier. Trust me.