What do you mean by attempting to breed? Were they fighting? Females should be kept in groups of five or more to prevent them from attempting to kill each other while they establish dominance.
If you have a male and female, they also should not be kept together unless you are attempting to breed them, and only for the duration of the breeding and then the female should be removed. The male should be removed once the fry are free swimming and no longer vertical in the bubble nest.
So, in short, they should probably not be kept together. The risk of your fish becoming stressed, injuring each other, or killing each other.
Seraphina - female halfmoon