Hooking up with someone once, twice, or very sporadically doesn’t have anywhere near the profound effect as hooking up with said person frequently.
When you are frequently hooking up with someone, it makes it that much harder for you to develop an emotional bond and physical attraction for the others that you are looking to date.
On the surface, hooking up with this guy seems to make sense.
Since you aren’t in a committed relationship and still have sexual needs, you get to use this guy to satisfy those sexual needs while you go about dating other guys in the quest to find a potential long-term partner.