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

I had a fling for about a month with a girl back in September. We had unprotected sex but I pulled out.... which I know isn't perfect. Yesterday, she called me and wanted to talk. Apparently she is pregnant and she is saying I am the father. I don't know if I believe her since our "relationship" was very casual. I don't really want to be the father either. 

I'm probably going to get flamed for this but I am married so its really preferable that this isn't my child. My wife and I have been going through a tough period and the fling was borderline cheating. We were apart but still together. So its complicated. Wife and I have been together for 4 years and we have a 3 yo son and an 8 month old daughter together. Since the fling ended my wife and I have been communicating so much better and we are in a good place again. This would fuck it all up. 

The girl I had the fling with didn't seem like she was going to have an abortion. She doesn't know I'm married so maybe it changes after that. I guess I would like to not be the father or there not to be a baby. My question is what should my move be? What do I need to be doing right now?

I'm 25/m and this girl is 20/f. My wife is 22/f.
<bot>: Had a fling for a month. Apparently the girl I had the fling with is pregnant and says its mine.  I'm married and have a family of my own already. Not sure what to do.