Omri, some serious stuff going on here.
Sadly, you are not the only one to ever go through this.
Please figure out some way of separating from this man.
Your only fear is actually the mildest possible outcome of this situation. I don't mean to make you feel worse than you already do, but if your H inflicts any injury to your DS (and this is likely) social services will be asking you questions. You are right, you can't control your H please start believing this through to the bottom of your heart no amount of appeals to his better nature or to what you assume he must feel deep down for his baby will work here; what you can control is the amount of distance you can put between your H and this vulnerable baby. This is the only part of your situation you can control. Please consider this seriously.
Either your H should leave or you should. Ideally, he should be the one to leave. But either way, you need to separate. The scary, dark angry mood, the refusal to change a nappy, to comfort the baby to sleep -- this man feels nothing but insane jealousy towards his own baby and is immature and irrational enough to behave like a sulking overgrown toddler when the baby intrudes on his reality. He has completely lost sight of what should be important to a new father. He is not protective of you but instead scares you into doing absolutely everything the baby needs done. He begrudges what 'help' he gives and feels he is being put upon. He is asking you to choose him or the baby.
In order to plan better for your future, go to Women's Aid 0808 2000 247 (they are busy around Christmas, sadly, so be very patient about calling and calling until someone answers). Or if you can afford individual counselling for yourself please, please go and take the baby with you. Do not leave the baby alone with this man.
Do you have family that you could move in with? Have you told anyone in RL about this?
The insane jealousy and anger he is exhibiting are part of the profile of an abusive man. Abusers do not just get jealous of alleged flirting with other men by their wives or partners. They can be equally jealous of their own children, and babyhood is an especially dangerous time for the children of the sort of man you are dealing with.
Please, if you can get a copy, read "The Batterer as Parent: Addressing the Impact of Domestic Violence on Family Dynamics" by Lundy Bancroft, Jay Silverman and Daniel Ritchie. Another that you should read is [[http://www.amazon.co.uk/Why-Does-He-That-Controlling/dp/0425191656/ref=pd_sim_b_1 "Why Does He Do That? Inside the Minds of Angry and Controlling Men", also by Lundy Bancroft.