I do not think Jeff will marry Gage, even for a child. In the episode where they were collecting their sperm (can I say that here?), Jeff told Gage he would have to adopt the child once it was born, so it had Gage's last name also. That is control.
Some things I think Jeff says and does because the camera is there. This weeks fight over the couches was not one of those moments. In his rage, Jeff totally forgot the cameras were on. You could see the split second terror look in those women's eyes.
Unless Gage loves angry make up sex, he needs to ruuuuuun before they bring a baby home.