If you enjoy each other sexually, you do so because you're comfortable doing it and because you want to

Boyfriend Benefit 3: Sex on Tap:

When he gets to have you, it's some of the best sex he's ever had. But it's inconsistent, because you're not there at his beck and call. You don't end up there every time he wants you at his convenience. You have other things to do, other friends to see, and perhaps even other dates to go on. The great sex happens on your terms when it suits you, and he misses it when you're not around.

You like him and you like the sex. You've already slept together, so what does it matter? You spend most nights there. Saturday nights become less about the girls and more about leaving early to have more great sex. You figure you can take your work stuff most nights to his place, because it just feels so damn good. You're there so often you can no longer think about the possibility of sleeping with anyone else, meanwhile, for some reason, he just won't commit..

Security/Loyalty

What's good for him is good for you. Even if part of you wants to, you don't commit exclusivity to him (mentally or verbally) if he hasn't done the same for you. You don't tell him you're not seeing other guys unless he says he's not seeing other women.