Hello,
I'm looking through the posts because I'm in a similar situation. I had 2 females together and the older of my 2 just passed away over the weekend. I'm heartbroken as she was the social one of the two... honestly the other is sweet but very shy and we never socialized her well. I hate the idea of re-homing her as I've never done that for any of my pets, but I don't feel it's fair to keep her alone.
If you decide that you want a female to try with your male after he is neutered made we could see if they would be a good match? My girl Wonder is about 5 years old. She was always very friendly with my other glider and has never tried to bite us, but we also don't push her to socialize with us if she doesn't want to.
Good luck with your boys!