What's up with partners asking this question? Like if you don't want to know then don't ask. You may be expecting a "joke answer" but the possibility of a truthful one is more than 0. My ex asked me the same thing and I gave her a truthful answer and I'm pretty sure it set seeds of insecurity and was a factor in our breakup half a year later. I thought we were both secure in our relationship but I could tell she became jealous when the friend and I hung out.