You are NOT doing this to your babies or him! I know it feels that way, I know because each time I have had a really early loss I have thought the same things, and I have said my husband would be best off meeting someone who can give him more babies because my uterus is like some baby killing thing. But in reality I know it isn't my fault, I don't choose to do this and the same applies to you, too. If you had a choice, you would choose to have a healthy pregnancy with a healthy baby at the end of it, but you don't have a choice as to what happens. For all you know, it could have been chromosomal abnormalities before, which could be you, him or both! And even if it was down to an issue with you and you alone, it isn't as if you're actively choosing to have a problem.
Ask yourself this: if you discovered it was his sperm and there wasn't any issue with you whatsoever, would you blame him? Would you want anyone else? Would you leave him? No! Of course not! Because you know it isn't his fault and it wouldn't be something he could help. Whatever the issue has been before, it isn't yours or his fault, it's life because sometime it's shit and it does some awful things but you WILL get through all of this, together. You will be stronger, because you will lean on each other and stick together because you love each other and that's what you do. There is no blame to be had here, he knows that.
I know this is all absolutely horrendous and you're petrified, but this could be ok. Things aren't set in stone. So far, so good. You have had some bleeds and spotting, yes, but that's incredibly common early on and some even continue to have periods throughout. Please don't lose all hope just yet. I know hope is a frightening thing to hold onto, but there is hope still.
Can you book a private scan this week instead? If you're more than six weeks then you may be able to see baby by now. It's an option to think about perhaps?
If things don't turn out ok, and I am praying they do turn out fine, but if they don't, please don't blame yourself and please know that your husband loves you no matter what and doesn't blame you, and everyone here is here for you too