No, not necessary. Over here that's a quite common combination.
But there are several good reasons for getting the girl spayed, especially if you keep them indoors. Intact does, depending on character, can indulge in quite obnoxious behaviours, like markintg their territory, or being "destructive" (they don't see it that way
), and those false pregnancys some go through frequently with a vengeance or sometimes hard to watch, and they can be quite annoying to room mates at times ( I have two pairs of intact does, and one was my house bunny for 8 months).
There's that cancer scare too, although there is indeed some risk that is a good reason to spay it isn't as dire as people like to claim.
Since all but one of my rabbits are intact, I can't say that there's a problem with staying bonded.Imho their social lives is more, well, lets say diversified, depending on mood and hormones, and they are over all more active than my spayed doe, but they make great teams. Rabbits are social by nature, that's not something that comes from spaying.