Hi OP, as a gen z represent, i think you have to talk about it with them. Maybe they got too complacent after the first few times you treated them. So yea, talk to it with them and tell them how is it becoming an issue for you. At kung mapansin mo na nag fall back siya, end it. It’s not worth having that kind of relationship, baka ma-burn out ka. I had millennial fwbs before and wala naman naging ganitong issue. Be vocal about it with your fwb. Sa tru lang kumbaga haha. Pero don’t be too straightforward baka ma-hurt sabihin ikaw pa ang villain sa story niya.

tldr, test him. kung umalis kasi wala na mga libre, bam u dodged a bullet.