Once he discovers that you don't want romance with him, he may show little interest in a platonic friendship. Try not to take offense at that. Be willing to let go of him completely.
If you try to continue spending time with him -- but on a no-intimacy basis -- you'll be setting him up for ongoing frustration. Most men aren't interested in a "look, but don't touch" relationship with someone they used to have sex with and still find desirable.
There's been threads started here by women who feel betrayed by a male "friend" who "copped a feel" that was not welcomed. I think they had unrealistic expectations.