In Virginia does the step parent have to pay child support for their spouses child

I don't know of any state that forces the step parent to pay support. They won't garnish a step parent's salary or attach sole assets. However, total family income may be used to calculate the support amount. Also joint assets (bank accounts, tax returns, etc.) may be attached to pay arrears.

Why isn't the other child's birth parent paying support? Thats who you should go after.

Smoothy, sounds like the other parent is the custodial parent and the OP's spouse is the one paying support.

AH... didn't see that before... but I can now.

Can you explain the situation better?