Where to go when we split, have 3yr old.

[SatNightIn]

My partner and I have been unhappy together for a long time and have decided to separate. We have a 3yr old son we both adore and live in partner's rented apartment which he's lived in for 25 years (has a protected tenancy agreement so won't move). He doesn't want to try counselling as he thinks there's nothing to salvage but wants me to move out and live nearby and has offered to help with the rent. He also wants 50/50 custody which I have explained will be unrealistic to begin with but he is happy to work towards it.
I have no idea what to do next. I work freelance and have part time work till november but rents around here are expensive and though it may work in the short term, can't see how the finances will work down the track. Also he's taken a back seat with parenting so far, working late and not taking many holidays so I've felt pretty much like a single parent up till now, with very little support when ds was a baby (my family live 300 miles away, his are near but there are problems and he keeps a distance). He blames me for our relationship breaking down and can be difficult to deal with (posted previously) bad temper, always criticizing, sometimes infront of ds so things very strained and feeling extremely stressed. Have been to counselling alone and counsellor thinks he's depressed but he dismisses it - and counselling.
Where do I go from here? Should I stay local, knowing I may have to move again in a few months or find a cheaper part of London to live in where I can manage alone and get to work. Want to keep things as stable as possible for ds. Anywhere we can go for advice as he doesn't want to try mediation either?

3 yrs old - he'll be starting school soon. I would assume that things will continue as they are your partner would have to make a much bigger effort to help out if you live somewhere else so it's unlikely to improve much and plan your location and housing on that basis.
If your partner is going to contribute financially towards his child including childcare/schooling I would take his wishes re location into account, if not then I would tell him I'm heading to live somewhere where you have some emotional and practical assistance assuming that is practical for your line of work.

I don't think you should make yourself reliant in any way shape or form, financially or otherwise, on a bad-tempered, critical, blame-slinging man that clearly wants to control you. I am very uncomfortable that he thinks paying maintenance means a) he can tell you where to live and b) he could take the roof from over your head if he wished. Get some legal advice on maintenance for your child and access agreements, do some research on benefits to top up your income, but then work out how you can live independently so that he has no hold over you. If that means moving to a cheaper part of town, go for it. In fact, I think a few miles between you would be extremely healthy.