I really don't like the sound of this guy, he really doesn't seem to respect u and what u want, i would say to leave him, you deserve better!
I also had an abortion, i am glad i made that decision and wouldn't change that...but it doesn't mean it is/was easy, i still think about it everyday(it was a year ago, and i had just turned 18 the week before)
I am also a catholic and felt as a huge burden lay on my shoulders...
But know this...
God has forgiven you, now you have to forgive yourself...i know its easier said than done, but is possible.
My boyfriend also didn't see it as that big a deal at the time, but understood how it affected me, wether wanting a child or not, loosing one is something only a woman can truly understand,
Its something you will carry with you forever, But you need to grieve and come to terms with it, and pray.
It took me a while before i felt i could pray or even go to church, as i felt perhaps i was not welcome because of what i had done, so i started looking on the internet, and found loads of sites teeling me that god forgives those who have had abortions and realises the burden you bear. Pray for your child, it helps!
I really do hope you are ok,
Best of luck with everything.
xxx