OP what a mess. I find a lot of comments here somewhat uncharitable - you had no reason to expect or in your wildest dreams imagine this, and you can't be expected to throw your current life away, shag everything up for your teens, to uphold a notion of how your husband should have behaved around 1970.
It really was a very different time contraception-wise, as I know because my father, though not a biker, also spent the 1970s being sexually incontinent. And my mother had to deal with the consequences.
That said, I 'd be unimpressed by him talking judgmentally about 'girls throwing themselves at him', especially as he clearly then made the choice to have sex with them without protection.
You're at the beginning of a long process here. As PP said, see what emotions come up, prioritise your and your children's wellbeing, demand your husband give you time to process without forcing his view of his past on you. Ask questions, demand answers.
I dearly hope for your and your kids' sake that he steps up and shows sone humility, patience and self-reflection.