Ex sex and how to deal

Me and my ex have sex all the time. We still have feelings for each other but know it will never go anywhere because he's afraid to commit, and I'm stuck in the past. The other day he messages me to come have sex..so I did. But everytime I text him to come have sex, he pretty much ignores me. It's like he wants it when HE wants it and it doesn't matter if I do.

Opinions please.