I would not add a female to his tank......they don't mix well and could kill each other or shred each other fins to the point of no return.
If you plan to breed do lots and lots of research, this species is not like or as easy to spawn/breed as livebearers. Feeding the fry can be tricky...
I love your Betta btw...he is beautiful...good choice.....and welcome to the forum too....
Also wanted to add, I like your back ground on your tank...did you make it yourself?