How about some evil betrayal fantasy? Your mom and wife plot against you and convince you to have a vasectomy for whatever reason. Then you get surprised when your wife gets pregnant. Your mom tells you that she hates to have her grandchild be like you, and your bully is more of a man than you'll ever be.
It doesn't have to be the bully, just your mom and wife bring random hot macho men, and they don't care if people laugh at you because you're a cuck. OR maybe your mom gives you sexual services, not because you're sexy, but so you'll have no energy for your wife.