Are you sure she really wanted the abortion? I only ask from personal experience, my friend and her partner fell pregnant young and she wasn’t ready but content to have a baby, he wasn’t and made it known through ‘gentle’ prodding. They didn’t have the baby, she struggled to let herself forgive herself and withdrew sex because she feared falling pregnant and losing another baby. He ended up cheating on her and broke up due to the guilt of it, both are absolutely miserable now still.
Obviously every story is different and you seem like a great guy, especially knowing you want to be with her and cheating isn’t on your radar as a serious option (everyone has temptations). I think she needs counselling because she herself hasn’t moved past it, for whatever reason she has, she’s sexually stuck in that period of time.
Also know, you’ve done nothing wrong (that I can see anyway), she’s not damaged and you didn’t break her. You both went through something difficult together, it’s okay to lean on each other.
I really hope nothing but the best for you two.