I have a 3gal tank that is divided into two with clear acrylic dividers I made. On one side, I have Rigel a male, the other side has Reena a female.
At first, Rigel would flare a lot and got really excited. He built a bubble nest and Reena tried to jump over several times.
It has been a few weeks now. Rigel still flares and Reena follows him around on the divider. I plan on breeding these two, so I will have to seperate them for about a week before I try, otherwise they will not likely spawn.
In your case, I would not suggest you put two females beside a male. He will never get any rest and it will shorten his lifespan significantly. In a 10 gallon, you can have 5 or 6 female bettas alone, and put your male's tank beside them. A 10gal divided tank is not all that pretty to look at, because all your decorations have to be small and live plants are harder to place. Thats what I would do anyway.