You need to get her fixed regardless of your other bunny. It doesn't matter whether you have him or not. Also, if it is a male, she is likely pregnant, so a spay right now before she can get too far along is all the more important.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry