The male will only try to mate if he has built a bubble nest. Has he done this?
I have never bred bettas but I know that the recommended procedure for doing so it to keep the male betta seperate and then to introduce the female carefully, often in a breeder first to keep her safe and then keep a good eye on them for agression, only once the male has built a bubble nest. If the male is not ready to mate he can kill the females. I would watch out for this as your bettas flaring is more likely to be agression if he hasn't built a bubble nest. The female is then removed immediately after mating.
It's not usually recommended to keep male and females together unless it's done in the way I mentioned so I would be a little worried if I were you unfortunately. Keeping them together on a long term basis is likely to lead to agression and possibly death. Is there anywhere else you can keep the females?
I have heard of males and females being kept together, but only in very large tanks, and where there is a large number of females (6 or so) and plenty of hiding places.
What size of tank do you have?