Everyone else has said everything that needed to be said, however, I thought I would offer a bit more background information in the hope that you will understand why people don't keep males and females together permanently.
The betta splendens we see in the store now is thousands of generations departed from their wild ancestors, and the result of that has been dramatic not just in terms of appearance, but in their behavior. In their native Thailand, farmers selectively bred bettas for aggression for hundreds of years--for them, betta fights were a way to compete with one another and come together as a community. They selected individuals with the sharpest teeth, the hardest scales, the best technique, and of course, the highest level of aggression. The winners of the fights would go on to become breeding stock, and the losers would be released back into the rice paddy.
Generations and generations later, Americans and Europeans began breeding bettas for the pet trade and shows, which caught on in Thailand and other parts of Asia as well. Many of the variations and colors we see now are actually fairly recent developments. It should not be overlooked that these fish have not lost the spirit of the original fighters even though they have gained frilly fins and fancy colors. In order to breed betta splendens, the male and female have to be conditioned for many weeks--even if they are properly conditioned, the male or female is often injured, sometimes severely, and sometimes fatally.
I'd like to point out that, while you aren't breeding, bettas are at all times aggressive. With each other, with other fish, with frogs, with snails, they simply are. Females and males alike. Just because you had luck in the past doesn't mean it will keep on going. Youtube it. I'm SURE you'll find PLENTY of videos of bettas attacking each other, and other animals in their tanks. Heck, there's a video in the picture forum of a betta that's lived in harmony with some frogs for forever, and then when she was filming he freaked out and attacked the frog. It was a hard bite, meant to hurt. If that was another betta, male or female, they would be in some trouble.
Another point is females are supposed to be less violent, thus no fighting. Untrue. Many females have to be removed from sororities due their overly- aggressive nature. Females can be just as, if not more, aggressive than some males.
In conclusion, I was actually thinking about this today, the whole, "Well, it worked for me in the past!" excuse... The question really boils down to "IS IT WORTH IT?" Is it worth risking the life of your fish? Or are they simply that... fish, to you? For 7 bucks more you can have a 2.5 gallon critter keeper, even less if you buy it used. You can even find plastic shoe boxes or plastic containers around your house to put them in. It's look to me like this is more of a case of being stubborn than thinking about your fish. Are you thinking about them? Or yourself?
While I agree that it's been reiterated enough times now that male and female bettas should not be kept together unless breeding, so long as members do not merely repeat themselves and things stay civil as they have been it seems there is no reason to close the thread.
germanchick09's experience appears to run counter to prevailing wisdom about betta husbandry and many members are likely interested in how things will develop between her fish, seeing pics, etc. The thread will be closed if and when there is a compelling reason to close it, but the fact that several members have shared their advice in a friendly manner does not seem reason enough.