<human>: Can you give me a shortened version of the text?

My long-time friend and housemate and I were pretty close.  He broke up with a girlfriend in December 2013 (9 months ago).  I've always been good friends with the girlfriend, even after their breakup.  Two months ago, I moved out of town for another job in another state.  While I was gone, his ex-girlfriend texted me weekly.  Now, it's become quite flirty.  I don't think she would be a great fit for a long-term relationship, so I haven't flirted back.

Also around this time, I was texting my friend about other topics unrelated to his ex and he has become unresponsive.  I plan on going back to visit all of my housemates and all of our friends.  I'm certain that I will run into the ex at a bar or something. 

What should I do about this situation?
<bot>: My friend stopped responding to texts around the same time that his ex-girlfriend begun flirting with me. What should I do?