The only time two bps should be housed together is very short term for breeding purposes. I would recommend grabbing three sterilite or rubbermaid tubs and set up three individual enclosures for them. Then if you WANT to breed the big girl with your bigger male, you could try doing so intentionally rather than just letting it happen by chance. But before you do decide to breed, think about the fact that you could end up with anywhere from 3-10 MORE snakes you will need to house individually...