Witnesses do teach that you can't get a vasectomy unless the life of the woman would be put in danger from pregnancy. They used to teach that sterilization was mutilation of the body.
It sounds like your health is in jeapordy, so he doesn't have a reason, even in jw land. The other issues are just, well, creepy. Something is really wrong with your husband. There is mental abuse already, maybe the potential for physical abuse?
Think seriously about what is best for you and your children.