can of worms don't do it find a girl that is child free.
the longer she lives in your house with her kids and you supporting her the more rights she has to stay in your home and bring anyone home she chooses should she fall out of love with you,if she was ever in love with you or just the home you could provide.The council will provide her and her kids a house,let them provide the house and take the relationship on from there .Never house a homeless women with kids