Love spells, thankfully, do not control someone's free will. They influence emotions which can affect free will if it was successful; however, this is subjected to belief. You may find someone who thinks it indirectly affects it. The concept of love is diverse. What was the purpose of this love spell? Was it to make him fall in love with you or attract different lovers into his life? Does he know you cast a love spell on him? Did he still feel a connection when you did?
There is little information to say if the the spell had this effect or not. It could be that this is his personality or your friend may not have much good luck with dating. He might be a player! Haha. I doubt the spell had much of an affect on this situation with the lack of information that was presented.
If the successful spell was to influence him to fall in love with you and he is no longer is, chances are that the spell was worn out. There are plenty of ways to remove a spell. Love spells, according to some practitioners, can be hard to remove especially from newer or younger practitioners. He could do a Return to Sender spell, the Lesser Banishing Ritual of the Pentagram, a salt ritual, or even try avoiding any form of love and lust during a short amount of time to remove the spell. You can always try to perform a banishing and protective spell or ritual yourself. If you are not skilled enough already, which may be realized seeing as you do not know how to remove the spell, you may not be able to successfully remove it.
Best of luck!