As long as you are both aware of the potential for, and willing to, crate and rotate if they end up not getting along, then by all means go ahead and get another dog. If you KNOW you don't want to live like that, if you KNOW you would feel differently about her (want to get rid of her, or put her down, or get rid of the other dog) if she attacks, hurts, or even kills the other dog, then no. You shouldn't get another dog.