abyssy how much does your partner do with your son, really ?
How much time does he spend doing something with him on a daily basis?
how much do you do for your son and him?
If say your oh doesn't spend any more than an hour with him a day, and doesn't help you with housework and your daily routine much. Then there is no need to have him around, then if you get rid of him and all his stuff its a lot easier on the housework load.
Also I've been a single mum for seven years, one of my children, the oldest who's 9 has special needs the youngest is three, there are hard times but its better than having ds1s father around to make my life harder trust me, also it really sounds like you oh may be emotionally abusing you i may be wrong but it might be worth having a little peek at an emotionally abused thread and see if it may apply to you.
if you really think your worthless and this is the sort of life your child deserves then go ahead put up with this crap.
my nan always said you can either put up and shut up, or kick off and kick out!
I do hope you choose the latter :)