Disclaimer: I don't own Supernatural. Kripke and a whole bunch of other people do. I'm just playing in their sandbox for entertainment purposes only.
"Hey, Ellen, can I ask you a question?"
"Sure, Sam, what's on your mind?"
"I…well, I was wondering if there was a way to propose to Jo that won't get me punched in the face. I mean, I don't want her to think I just want to get married because I feel obligated to because of the baby. But with the mood swing she's been having lately, I don't think I'll get the chance to explain myself before blood goes squirting out of my nose."
"Then why do you want to get married?"
"Because I love her, and because I realized something last night when she told me she was pregnant: for a long time, I thought that if I told her how important she was to me, I'd just be setting myself up to lose her the same way I lost Mom and Jess and Dad. But, I guess us finding out we're having a baby made me think that maybe I've been letting the demon have too much power over me. By being so scared that I'd lose Jo, I was stopping myself from having the chance to be happy. I want to be happy, and I can't do that without Jo and our baby. So, how should I propose?"
"Oh, I should probably just tell her that, shouldn't I?"
"Good idea, Sam…just leave out the bit about her mood swings."