My husband has a child with a woman that he was not married to. They currently have no court ordered child support order. My husband just pays a certain amount a month. Now, due to problems with the child's mother, my husband is considering putting himself on child support and getting a court order for custody/visitation. Will the courts factor in that my husband has 2 kids with me in our marriage in the maount of support that he pays to his son's mother?

Depends on the State - and whether you work. Custody/visitation and support are two separate issues. HE files for visitation; SHE files for support.

In NY the Courts take the stance that your husband KNEW he had a child to support and then went on to have two more children. The first child should not have to suffer.

I don't know where you are.

I am in Illinois and I do work.

This link:
Calculating Child Support Obligation (http://www.childsupportillinois.com/general/calculating.html)
might be somewhat helpful.

I don't see anything on that website stating that the general 20% would be reduced due to your husband having two additional children.

I know my state(Wisconsin) doesn't list the information very clearly but when it is a case of shared placement/physical custody(when the non-custodial parent has the child more than 25% of the time), they will factor in the incomes of both parents and base child support off that. Anything else uses the established guidelines of X% per child.

Will the courts factor in that my husband has 2 kids with me in our marriage in the maount of support that he pays to his son's mother?

Generally-no. :p