Hi Merhaba
Sorry you are going through this
Most definitely talk to a lawyer. There is no saying what he will/won't do - addicts are unpredictable
In terms of visa - I am not sure I am following - I always thought that the only entity that can cancel it is the entity that has given it out - I.e a governmental body of some sort. Sounds like he is not around to be told about the visa anyway.....unless I misread it?
You need to protect your finances/assets somehow. The fact that he lives/works does not affect you financially, unless he starts being difficult with the settlement.
Find a lawyer who is skilled in family law of a country where you got married and also familiar with local laws. In some instances - if spouse goes MIA divorce is still very much possible.