Dump him? 
that's a bit extreme isn't it? On a couple of moody bouts from a 13 year old? Gosh, if we all acted so swiftly to do what 13-year-old girls dictated we'd be in a right mess.
She's 13. it is quite normal at that age to be sulky and grumpy, unpleasant even, so let's not get carried away with damning this boyfriend before we know the first thing about him.
He has popped in a few times, and so your DD hardly knows him to dislike yet. Perhaps she would be like this whoever he was. Perhaps she needs some time to get used to him and the idea of you being in a relationship with somebody new to her.
You could, at an opportune moment when things between you and your DD are peaceful and you are alone, on a walk, say, talk to her. Say she she's made it obvious she doesn't approve, and is there a reason? Or, you could take your time over this, give her a chance to get to know him gradually and in her own time. How about some kind of nice outing involving him, you and the dcs, then he can make a gesture, like buying them an ice-cream or going on a ride to whatever.
She can't be expected to just like him automatically, that would be an imposition. But she can be expected to behave with grace and good manners though. In the meantime, if he can keep making the effort, and not take personally her behaviour or words, behaving like a grown up in other words, then perhaps progress will be made.
If you 'dumped him' - then the message your DD would get would be if I don't like something/someone, then I just behave badly, rudely, and DM will instantly take action against them.
Talking to your daughter would show her some respect and make her feel important, and listening to her give her reasons why she doesn't like him. She is probably just jealous, Op, and needs a bit of help.