Hi OP,
Pretty much the same thing happened to me a few years ago. My dad ran off when I was 2, never showed an interest or paid a penny towards my upbringing, but contacted me on Facebook when I was in my mid-20s. I was a bit curious so accepted his request, but I wasn't interested in suddenly calling him daddy and playing family (he apparently thought about me every day and had two younger children who were "desperate to meet" me).
We exchanged a couple of emails, I gave him a potted history of my life and said it wasn't a great time for me to become familiar with him (it wasn't, I had other stuff going on).
He then started to get a bit pushy saying yes it is a good time, we have no reason to not start a relationship now etc... and I had even less respect for him (not that I had any to start with, it just became minus 5 rather than zero). So I told him where to go. My mum didn't know about it but I think she would have been upset, but she would have known I had little interest in idolising a man who abandoned me for the most difficult part of my upbringing, so it wouldn't have damaged my relationship with my mother.
A few months later he sent both me and my mum a message about a massive sport event cheering on our team
my mum was very confused and we just laughed it off.
As you have said, ultimately it's your decision but I understand why you are upset. Try to not be offended however your daughter proceeds, it doesn't need to affect your relationship and has no bearing on her respect for you and your husband, and I imagine she already feels a bit conflicted. If she decides to tell him to bore off, great (in my opinion). If they get to know each other and it turns out he grew up after being a useless father then there are worse things in the world than them getting to know each other. If curiosity gets the better of her, she gets to know him and he turns out to still be a knob, she will work it out pretty quickly.
I understand why you are hurt but I wouldn't worry too much. I have a friend who is in a similar position to me and her dad was exactly the same - pissed off from the age of 2, reappeared in adulthood and then started making demands for a father-daughter relationship as if he deserved one. She was as unimpressed as I was in my situation. Your daughter may well be the same, even if she wants to give him a chance.