Since Sandra can't have children and isn't getting any younger and needs publicity, Jesse and Sandra sue Janine for sole custody of Janine's daughter Sunny.
The custody fight is almost certainly over child support money. If they can get sole custody they won't have to pay her a dime.
I don't even think there is child support. I remember hearing Janine was given a huge lump sum, already spent, just to go away after DNA tests came back that he is the sperm donor.