I think you really needs to talk to a divorce and estate plannin

You need to sit down with them and do some calculations: which way you can get more money for your child -- divorce now or not.  If you think you cannot afford lawyer fee, you cannot afford not to have sound professional opinions.

It seems some divorce case can drag on for a long time. Your child might be better off if the divorce is not finalized.  E.g., you can get his 401K and social security payment if stayed married.  (Your minor child can always get SSN payment.)

On the other hand, if divorce with a reasonable agreement, your child might be better provided. 

It is not the time to save money.