He is being stubborn cos he know's it'll upset you cost you money.
If the options are:
a), walk away and get nothing, letting him keep it all, or
b) pursue what is rightfully yours, even if it means all the asset value is absorbed into legal fees etc,
then I'd be wanting to pursue through the legal process, cos if I am likely to get nothing anyway, then I'd rather fight for what is the right thing to do! It sounds as though he will fob you off, hoping that you will walk away & he'll get the lot.
Let him know that is NOT the case, send a demand for a reply & then ACT, if you do not hear back within a stated reasonable time.
Bear in mind though that money is just money, a means to an end & it may well be that you forgo this money now but have an easier life later on. OR you fight fr what is rightfully yours, see what you get out of it.
I had no financial assets to split with my ex but he has still managed to keep me & out son in poverty for a decade...some people as just plain nasty, others are hurting in their own way & lashing out in their own way.
I wish you well & good luck!