Can't seem to finish

Ok. Very strange thing going on. I just recently got back together with an old flame - ex-girlfriend. We dated for 3 years about 3 years ago. During our first try we had a pretty active sex life. nothing crazy, just regular happy sex. We were both able to finish and everything was great. So now we've been re-dating for a few weeks and have gotten hot and heavy. I've been able to satisfy her at least two or 3 times a night. Problem is, no matter what she or I do, I can't finish. And she's trying really hard. In fact she's gotten a little more sexual and talks dirtier and is much more enthusiastic about everything. I'm not sure what to do. She's getting a little upset because she thinks I'm not attracted to her.

I know this is kind of vague but any advice would be appreciated...

Try to incorporate you masterbating yourself into the routine. Then try doing it with her. This way you can "relearn".
It could be due to numerous other reasons aswell...so try to seek them out...make sure she knows it isn't her.

I know the feeling of not being able to finish, and how embarassing it is...so keeep communicating, eh. Work smarter not harder :D

Another thing is, spread out your sex sessions. Me and my girlfriend used to make it an every night thing, and for the most part I got off easily. However there where times where It took me forever and sometimes...I couldn't. I can't explain it really, except maybe I was getting used too it. Course we tried new things and that always helps. But just try to balance the sex "time" a bit.

Thanks for the responses. I'm going to try some different things. And hopefully get there!