Males and females should NEVER be kept together. The male is aggressive even towards females and will eventually kill her. Even spawning is a violent affair that results in a lot of fin damage to the female and sometimes death. They need to be watched constantly until the spawning is done and the female removed right after to prevent the male killing her. Breeding Bettas is not as easy as breeding guppies and should not be done by anyone who hasn't done a LOT of research and has a plan for finding homes for many babies. It is also expensive and time consuming as the males all need to be kept in separate jars which need to be cleaned every day to prevent fins from growing out deformed.
IMO I wouldn't advise keeping a male and female even in a divided tank. Seeing each other keeps them in a constant state of being in "spawning mode". The male will be preoccupied with constantly building bubbles nests and the female may produce a lot of eggs and possibly become eggbound and die if she cannot release them herself.
I had a male and female in separate tanks but next to each other and even after the female died (of dropsy) the male was stressed for many weeks building huge nests and looking for her. He wasn't his usual playful self and was becoming obsessed. He's "almost" back to normal now. I know some here do keep males and females in divided tanks but IMO, if you can avoid it, it will be better. I keep my males and females on opposite sides of the room now. This way they continue to interact and play with me rather than being stressed and obsessed with spawning (which I will NEVER do.)
If you can get another tank for the new male, possibly a 5 gallon or larger, and just enjoy his antics and personality with his mind focused on YOU.