I have been on the other side of things, so the new and pregnant girlfriend. My husband and I met and got engaged quite quickly, and we found out we were expecting a few days before our wedding which was ten months after we first met. Husband's ex was less than impressed and I can understand why as I'm pretty sure she still had feelings for him (I don't mean to imply you do!) and they also had a child together who was quite young at the time.
My husband moved out of the area when he moved in with me, but still maintained contact with his child regularly. He had a heck of a train journey each time, taking three hours each way! I don't understand those who don't maintain regular contact especially when they still live close by as well.
His ex, because she was quite angry, made things awkward and eventually after threats of "you won't see your son" all the time, he went to a solicitor. He tried mediation which she didn't turn up to, but she then agreed times he could see their son. All was fine initially and then it wasn't, she stopped him seeing him and my husband went back to the solicitor and it went to court, where firm rules were laid down. It's sad it had to come to that, but sometimes it can be helpful to have someone else acting as referee and laying down plans for each party to stick to. She was fine after this, and we all got along ok. I would like to think we were all friends after that.
Maybe if he isn't seeing your child regularly you could try mediation? Come to an agreement? I can understand your concerns especially if he isn't already maintaining contact. Your child should be seeing him and he should be making every effort. His future child/ren don't come into it, where maintaining a good level of contact with the child he already has is concerned. Obviously when this child arrives, things will change BUT that shouldn't mean he sees his first child less. Most of the time when people split up the non resident parent sees their child at the weekends, this seems quite a common arrangement and it's an easy one to keep up with most of the time. I think you have to contact him and arrange to meet up to talk contact through properly, if you can't come to an agreement or he doesn't maintain an agreement you come to, then perhaps a more formal mediation appointment should be made
