Going on first date tonight after breaking engagement...

My now ex-fiancee and I were together for 3 years. Tonight I am going on my first date since we have broken up. I am kind of nervous but the thing I am most worried about is that I am going to talk about him too much. I live in a very small town, a little over 15,000 and most people are here to go to and engineering university (I moved so the ex could get his PhD) and normally everyone's first question is so what brought you here. Off the bat I have to explain I moved with my ex. For the last two years we have had the same friends and done a lot of things together. So when people ask why did you travel to xyz I don't want to lie and just day I went with a friend when I really went with my ex for his conference. I did do things on my own but this is a very small town and activities are few and far between. My question is how do I now seem like I'm hung up on my ex and keep talking about him (I did this with him, I did that with him) but not lie. I'm not looking for anything long term right now but I don't want to lie and it come back and bite me in the butt later.