Erica doesn't want to be paid off. She makes this very clear to Cooper, who was completely clueless about the check. This leads to a big blow up with Charlotte, who goes ahead and does her own paternity test. As it turns out, Cooper was right. Mason is definitely his son.
Addison worries Sam may leave her if she gets hormonally out of whack from fertility drugs. Jake becomes a sounding board for both of them. Sam asks him for the 411 about women on fertility drugs. What he says obviously has Sam a bit on edge. Then Addison wants a man's point of view on her situation even though she doesn't know Jake very well.
Jake gives Addison the capsule summary of his life. He has three sisters and has only ever been in love once. Jake also says he's always known Sam to be a stand-up guy. He adds that her own instincts are probably way better than any thoughts he could throw her way. Addy fesses up to Sam that she's worried he'll leave her if she has a baby. Guess time will tell if that'll ever happen.