Hiya - sorry, have been off again, working and then away for a family 'do'.
Sounds like you had a really horrible w/e - so sorry - and sad, because you should be able to celebrate children's birthdays not just for the child's sake, but as parents - 'aaaaah, can you remember when he was born' etc. I had noticed that you held the party at your Mums (and can guess why that would be a good idea!) - but horrified that he has neither attended (let alone helped) not bought dS any presents .
I can see why you don't want to rush to live with your mum, either - you should have had his jeans ready, ffs!! And if there is no tumble dryer and he won't have clothes drying in the house, then his jeans will tend to get damp in the rain, won't they! Unless he thinks you have the power to change the weather, I think he had better take his stuff to the launderette!
This isn't about jeans or launderettes is it though? And I don't know how far it is worth causing hassle in order to argue through ONE aspect of his treatment of you. IF you think he can change, and you can save your relationship, it would be worth fighting through these individual situations - and a whole lot more would have to happen besides - like him go to AM, learn to love the children like a proper dad, deal with his obsesive problems, etc etc.
If in the longer term you are aware that you will have to, and want to leave him, I think you are better conserving your energy and focus to that end. Save money where you can (what would he say if you said 'oh, by the way DS's presents cost this - since he thinks they are from both of us, will you be paying me back any of it??' Then you could squirrel away the money he gives you - but not pursue it as a row if he doesn't offer any), continue to seek financial and legal advice, go to your course and gather energy for living alone.
And remember, HE hasn't been your whole world for 10 years - you have had children for the last 6, you have friendships, you have your job and good relationships with colleagues - there is a LOT more in your life than him.
But I know it is a serious change, however horrible he makes life!
Anyway, once again, give yourself a huge pat on the back - against all the odds, you gave DS a lovely birthday, a great party, and obvioulsy a Thunderbirds Rocket has made his little heart glad. WELL DONE! You are a great Mum.