Female and male betta fish question.?

Every night around 8:30pm to 12AM my bettas are always acting strange. My Red male betta always go up to the surface and open his mouth, I think he's trying to blow bubbles, but he can't because I think he's still young. He does this every night and he gets really angry then hides in his cave for a long time.. My female betta always looking depressed everytime the male betta is hiding. I don't know much about betta but I know they can't be kept together.. I have a divider for them, and they always communicate throughout the days, but when is night time they always act strange. The female betta is way bigger than my male betta, but I think she likes him.. I think he likes her too, but something it's not right. I don't want to breed them and have little betta babies.. I just like to keep them in the divider and let them communicate. They are healthy, and eat like pigs but every night they are always acting strange. Should I release the dividers, and let them touch each other but keep a close eye on them? Again, I don't want little betta babies.. I think my female betta is ready to breed, but my male not because there's no betta nest, but he does like her.. Should I take the divider out and see what happens?