Jerry Seinfeld? I don't think so

My boyfriend has decided he's hilarious and that with my writing skills and his humor, we should write a comedy t.v. show. No, he's not joking. He's been hounding me to start for over a week now. But here's the problem...my boyfriend's no Jerry Seinfeld. To be honest, he's more of a George Costanza. He's even got the whole short and balding thing going (don't get me wrong my boyfriend is much more handsome than George!). But he's about as funny as George. He's not. But he thinks he's a riot. We'll talk about something (usually something that's not really that funny) and he's like "Now that's funny. I could do a whole comedy routine on that. We could put that in our show." Then he does the whole Timmy from South Park thing "Have you seen this? Have you heard about this?" . These are his characters so far: a girl who things that every guy she dates is weird. There's always something wrong with them (much like Jerry) and a girl who loves the 80s and worships the Teenage Mutant Ninja Turtles. Now that's funny he says. Um, not so much is what I"m thinking. Actually I usually do laugh my ass off while watching him tell jokes because HE thinks he's so funny that I laugh AT him. It's kind of cute watching him though as he gets all proud at himself for his lame joke. Oh god, I really hope he doesn't read this one or I'm going to be in trouble. So how do I tell my boyfriend that writing a comedy will be a waste of our time because NEWS FLASH: YOU'RE NOT FUNNY!