Have you talked to him Bubbleezz? Tell him your concerns. Communication is the key here.
If you can't talk to him, try mediation. Google National Family Mediation (NFM). If your ex is slow off the mark, do it yourself. Do everything you can to avoid the pitfalls some people experience.
As for the previous post If i was you i would only let your xp see the baby maybe at your place, your parents house(or his), the park, a baby club' I would say keep an open mind'.
If you intend to do this, consider carefully why you are. Would the baby be at risk with him? Would you stop it because he doesn't have experience with babies (and if so, how does any new mother - or father get experience? neither men or women come into this world with an innate ability to care for children, it is learnt)? Would you do it simply because you're the babies mother and you're `in charge'?
Do the above and you're sending a message that he is a danger to his own child. If he is, fair enough.
Do not take this as a starting point. It is an excellent way to end up in court if you're unlucky.
For the record: If he's just started seeing someone else it is a little unreasonable to foist her on a new baby.