I had the same problem. I started mating my guppies in Sept and even though I had luck with a handle of fry that survived from 3 set of pregnancies, what followed as turned me off to guppy breeding for now.
It is recommended 4 females to one male guppy. Is the male a tuxedo cobra? Those are the worst. They are like rapists, not to make light of it. They usually stick to one female and stress her out to the point of killing her - and it's a slow death.
Add more females to avoid this uncomfortable situation. I hope you do it soon because she may not survive. This happened to me many times in these 2.5 months and I lost all 8 of my females, because I would add them in one by one instead of as a group. Also, I have seen them die hours after giving because they get so stressed during breeding. Good luck. Oh and with 10 gallons, I think you can do 5 or 6 guppies, max.