yanbu - and I'm waving a warning flag about this behaviour.
I think it is quite reasonable of him to come to one or two groups with you, if he is going to be taking DD without you (and good for him). Baby groups are very mum dominated, and that can be hard for a dad, if he's the only bloke in a room. I think other mums will be more likely to at least say hello and try and chat if they have met him before with you (my dp is a hands-on dad, and this is our experience).
BUT.... no, you do not want a lost puppy deadweight with you, sorry. My thoughts are - if you are in an area where you don't know anyone, what is HE doing, with or without DD, to meet people and make friends? Does he have hobbies, do sport? Will he socialise with work colleagues?
Or is he expecting you to make a social life for him? that really won't work. Friends YOU make want to be friends with YOU. They will most probably be polite and try and involve your dp too, if they really like you! but if he can't be good company in his own right, it just won't work.
Being blunt - I met a mum I really got on with via baby groups, and she often had a husband trailing around with her. He was virtually mute and just very hard work (she was very funny and lively). We went on a few days out with our babies where he came too, and it was just awkward as hell. A couple of times she mentioned the possibility of her dp meeting up with their ds and me/mine when she was at work/away, and I'm afraid I got cold feet at that point. It wasn't fair on me - and it was just an odd feeling, that she was trying to make friends FOR him, as a grown man.
I think introductions are fine, btw - but if he isn't making friends himself, he can't make your friends, IYSWIM, and it will probably stop other mums befriending you to some degree.
If he feels awkward at these groups, you could ask your hv if there is a dads and baby/toddler group in your area, and get him to go to that. But really, it's not just about baby groups - if he isn't making an effort to make at least a few friends/social life for himself, then you're just going to turn into the wife who has to go everywhere with him and speak for him.