You need to get a second pot. If you keep them together and one is male but the other is female, then you will have to cut down the male if you want seedless bud. However, you will not be able to remove the root of the male plant because it will have grown intertwined with the female's roots -- and if it starts rotting, then that's going to cause a big problem for the female.
However, if you don't care if you have seeds in your bud, then if one is male and one is female, you'll just let the male grow along side the female -- but that's also a waste of nutrients and space that the female could be using, as another poster pointed out.
So, all in all, it's worth getting a second pot.