As others have suggested, this is a problem of expectations. Yours were that once things started to become intimate and 'caring', at least overtly, there is an implied and automatic 'exclusivity' to the relationship. It doesn't work that way, at least not these days.

His expectation seems to have been that even though things have gotten intimate and 'caring', no conversation about expectations is required. While that's "technically" true, even the least observant person should have some idea that human nature equates intimacy and caring with exclusivity at some level. Once you're sharing your bodies with each other, it's just plain common sense to open the discussion enough to establish STD risk, etc.

So I think you've both contributed to this situation.

Now, on to where this leaves you. You're interested in being exclusive with this guy, and he quite obviously isn't thinking the same way. Assuming that you want to pursue this at all, it's high time to have the 'exclusivity' talk. And it needs to be explicit, with no room for misunderstanding. This is no place for hinting or metaphor. It's best broached in lightheartedness and fun, but you need to have the talk. Given his recent behavior, especially that he's actively pursuing other matches, don't be terribly surprised if he's either a) not ready to "settle down with one person", or b) may continue his pursuit of other women regardless of the discussion. I hate to say the latter, but it's possible. "Trust but verify" applies in this situation, given the existing history.

In any case, if the result of the 'exclusivity' discussion is that he wants one thing and you want another, it's time for you to move on to someone else.