O_o uh... Alright... My first question is why slip blood [menstrual, miscarriage, nose bleed or whatever] into your loved ones drink? I don't understand the logic.
Does he know? If he does I doubt it's the family turning him against you. I would say sorry, then sit down and talk. [Get a councillor] You might be better together, or apart, you don't know, but it's best to be honest than manipulate [magickally or mentally]