Starting 18:04
Mark: If 20 years ago I had gay sex, am I going to tell my wife that? No!
Ian: I would, and I have.
Mark: I understand you would. I know you have, and--
Ian: All right.
Mark: I don't think less of you for it. I might jibe you about it every once in a while, but that's it. No, no, no!
Ian: I guess I'm just a little more forthcoming in my relationships than you are.
Personally, I'm leaning Mark on this one-- being in a relationship doesn't mean that you need to divulge your entire sexual history to your partner, or even that they want to hear it. But if your partner asks "Have you ______?" I think you should answer honestly.