Talking about the exes during a date.

So I went on a date tonight with a guy. We were having mildly interesting conversation, you know, ice breaker stuff. Then he starts talking about the other dates he's been on and how people date him for a month then dump him. Starts telling me he doesn't know why people won't go out with him and how much he wants a relationship. Pulled out his phone and showed me all the guys who have dumped him.I'm sitting there thinking 'wtf is this guy doing?' Anyway... After dinner, we'd arranged for him to come over and play some video games, but he got a call that his mum wasn't feeling well or something (I suspect it was a soft out that he didn't want to take...) we ended up walking around for a while and then I insisted he go home to be with his sick mum, as he would regret it if something happened.What do you do when someone doesn't want to shut up about their exes? Also, how do i politely tell him I have no interest in being the next months fling...?I know I could just ignore him, but that doesn't feel very grown up. Also, if you've got stories similar, would love to hear em.