Once it's revealed that he not only slept with someone first, knocked her up and purposely withheld it--Ric will rightfully use it to get Willow full custody. Michael will be left with Wednesdays and every other weekend.
I have a feeling it won't come out until after the baby is born--but I hope I'm wrong. I think Michael will win full custody, the truth will come out when Sasha gives birth and then Willow will take Michael back to court and gain full custody. I truly hope not though, I don't want to see two custody battles.