Your ex sounds exactly like mine. But it does get better. I am two years down the line of a horrible divorce and still living in the same house as the Final Hearing happened just before the lockdown. But it feels so much better knowing that I am free and have the rest of the life ahead of me and he can never ever control me again.
First of all, do not worry about his expensive and pushy lawyers. If he doesn’t offer you a fair deal, you will go through the court and the judge won’t care how expensive his lawyers are. You have a small child, therefore the court’s main duty is to assure that the child’s needs are met.
The court needs to offer you the settlement, which will allow you to house yourself and your son. If you are the primary carer of a small child, the court will take it into consideration when making the decision on splitting the assets. The court will look into the mortgage capacity of each party. I was granted much higher share of the assets as my mortgage capacity is lower.
I was also scared of ex’s lawyers, but in the end the £45000 he spent did not matter at all. In fact it worked in my favour as the judges ( three hearings) were very sympathetic to me as I was self representing. One of them reaped the barrister to pieces for trying to mislead me.
If you can afford, find a good solicitor who can advise you along the way. I had a wonderful one and went to her with all the important bits of work such as analysing the financial disclosure, proposals, preparing for the hearings.
I know it feels that there is no end, but there is. In the worst case scenario there will be the first hearing, the second hearing and the final hearing. I ended ticking off the days to each hearing on the calendar. It really helped me to see the numbers go down ( and drove ex bonkers which was an added bonus).
As pp said, focus on the final goal, which is a better life for you and your child.
With regards to ex saying that your son would be better off without you. Rubbish! Why would your son be better off being raised by a bully?
Of course your mental health will be affected by the divorce, it is a lonely, soul destroying experience. Only the bullies like my and your exes get a kick out of it.