Accepting of what? You don't have any kind of commitment. You don't really even know this guy.
You may both be interested in a monogamous relationship, but neither of you are in one. He may be serious, that he wants to get to know you, but he doesn't know you yet. May be he doesn't want to be in a relationship with you, maybe he just likes to hang out with you, maybe he hasn't decided yet, maybe he's just yankin' your chain, who knows, in any case you have no promises yet, and he's not obligated to change his ways until he commits.
You haven't gotten him to commit to you, why are you feeling hurt that he's not acting like a man committed to you? If what you want is the fairy tale of some guy who's just consumed with obsession for you the moment he lays eyes on you, obviously this is not the guy for you - and now you know that, thank god you found out way early. Move on. YOU have no obligation to stick around either, and if his behavior so far is that objectionable to you, why do you think you're right for each other?
If however you realize that healthy guys do not, and will not, commit overnight, give him a chance, he may still disappoint you, he may still be an ass, but c'est la vie, if you never toss the dice, you never win the gamble.
Look, until you have that conversation, and get that agreement, there is no relationship. He's got no obligation to be monogamous for you. And while I understand that you got your feeling hurt, he didn't do anything wrong.
I run far and fast from guys who think they're my boyfriend overnight, and start acting like jealous housewives after only a couple of dates. He may be like me, it takes me a long time and a lot of communication before I'll even consider making a commitment - and yes I do like being in a relationship, and I will say that, but I'm not gonna put my life on hold in the meantime. However the moment I make a promise, I keep it.