My first question would be are you SURE you’re right about him? Some people come across as the “player” type because they’re naturally more extroverted and flirtatious, especially when single. Is it possible that he’s actually a “good guy” when he chooses to be in a relationship? (I know a couple of people like this…men and women. When they’re single they are very flirtatious, date lots of different people and are very “out there” but in reality are very loyal and honest people. When in relationships they don’t “play” their partners and are monogamous and trustworthy.) If this is the case, you need to decide if you wish to find out if he’s interested in pursuing something more with you.

If he’s truly a no good player that you still have feelings for you need to decide if the struggle to contain the feelings is worth the platonic friendship. Only you can make that decision.