It doesn't really matter what anyone else would do.
From his response, you can tell that he sees his future with his girlfriend. He never intended to leave. So, you need to end things with him and not let him worm his way back in. All of the lies that he told you were to get you into bed. That will hurt, but you need to accept it now so that you can make the best plans for yourself.
If you'd never forgive yourself for a termination, then your options are to have the child as a single mother, or to put the child up for adoption. If you have the baby, plan to have it on your own. You can chase him for child support, although your post doesn't make it clear if he actually does have a good job, and I believe that the amount he has to pay will be reduced if he has other children that live with him. It'll be something, though. Don't plan on him being around or having any contact with the child, though.
It's highly likely that he won't tell her, but if she finds out, she might leave him - in which case he runs to you as a back up plan, or she might move with him away. Be prepared for both. Don't be his back up plan, because he'll do this to you too. Honestly, you can't afford to invest anything else in his lies and crappy fairytales. Protect yourself and your unborn child.
What happened before is almost irrelevant now, but you need to make sure that you can see his lies for what they are, and that you protect yourself from them going forwards, or you'll open yourself up to a world of pain thinking that "maybe he's different" - and he never is.