I have been divorced from my ex-husband for 3 years. Marriage produced a daughter 13 years old and a son 4 years old.

The other day I see in the mailbox a lawsuit to contest paternity on my son. I was shocked!

He decided to pay me back for filing for child support. I call my mother-in-law, and she says her son got married and doesn't want to support someone else's child.
But when I was pregnant, he knew my son wasn't his and asked me on his knees to keep the child.

And now he's backed off. What should I do?