The problem with rams is that they need to choose their own mates. We can't buy just any male and any female and expect them to 'like' each other. They may get on together for a while, then one will quite often turn against the other. This seems to be what is happening with your rams. Buying another male is not the answer because the female might not 'like' him either.
As the two you have now appear to have 'fallen out' with each other, you could well end up with a dead ram as one is likely to kill the other. The best solution would be to separate the male and female.