Ontario: Separated, pregnant through IUI, divorce not finalized. will my ex have parental rights?

I’m in Ontario and currently going through a divorce. We were married for three years and separated last year. The divorce is still not finalized because my ex and his family are refusing to provide financial disclosure and seem to be stalling the process. Their lawyer told my lawyer that he wasnt going to sign something fraudulent???? First time my lawyer heard something so insane. He is legit deranged.

I’m currently 8 months pregnant. The pregnancy is not biologically related to my ex (I conceived through IUI after we separated).

My concern is what happens legally if I give birth before the divorce is finalized. I’ve heard that in some places a husband is automatically presumed to be the legal father if the child is born during the marriage, even if they are separated.

If that happens in Ontario:

• Would my ex automatically be considered the legal father?
• Would he have any parental rights to the baby?
• What steps would I need to take to prevent that if the child is not his?
• Can this be addressed before the birth, or does it have to be dealt with after?

I’m mainly concerned about protecting my child legally and understanding how Ontario handles this situation.

Any insight from people familiar with Ontario family law would be appreciated.