My ex told me this when he broke up with me. A year and a half later - he is still single. And happy (as far as I heard). Some people really don't want to be in a relationship, not with you not with anyone. But that doesn't change the fact that you should run away as far as possible because no, they are not gonna come back to YOU. When they are ready, they will find someone new. That someone new will make them be ready again. You've been there, done that - it didn't work out. And he knows this. So just move on.
It means "I wanna fuck around until I'm tired of that and/or girls stop opening their legs for me, BUT I'm gonna tell you I'd date you in order to keep you on my hook for whenever I can't get any pussy."
That's a load of BS. If they think you're worth having a relationship they would be in one and not make up some shitty excuse about not wanting to be in a relationship. Sometimes we girls also tell guys that we just want to be single but we know it is just because the guy asking you out is not really what you are looking for. Honestly, tomorrow another girl might catch his attention and then he'll be more than ready to be in a relationship. The only time I feel that excuse is reasonable is right after a serious relationship has gone to dust.
Although at this given time, he is Not into the Love Line in Being in a Real Relationship, You are the kind of girl Whom... He would bring home to dinner. No, don't wait here, dear. One never Knows how this Goes. Go about your life right now, stay friends for now, and if anything changes, you will Hopefully still be in the Plan with this Man. Good luck. xx