A lot of guys like the feeling of being in a relationship, without the actual responsibilities of having a real relationship.
You (in a perfect world) should have stopped when you had feelings, brought it up and he brushed you off.
If you’re the depressive type who reads deeply into a guy sharing beer he likes with you, or tells you he misses you (the sex?) after you haven’t seen each other in awhile, you should not be trying to do FWBs because you aren’t able to do that. It’s okay. A lot of people cannot. I don’t think he’s giving you too many mixed messages, but it’s not good that he keeps seeing you knowing you have feelings for him.