I have read somewhere but i dont know about its authencity nor do i remember teh source that in islam if a husband leaves his wife and go somewhere without her permission for more than 6 months then she has the right to seek divorce.
my advise to you is that your 1st choice shd be that he takes you with him . you are married and husband and wife are suppose to live together thats why they get married. he is supposed to provide for you , protect you and by living abroad he must only be fulfiling his financial responsibilities.
2nd. if you agree and he does go abroad and u wish to live as his wife forever then choose to live with your family not inlaws (offcourse if your family supports u ) . you dont have any obligation to live with his inlaws or to take care of them. you can also ask for a seperate and safe living its your RIGHT.
I am sounding meany and money minded but thats the only way you can secure yourself and plz dont compromise on any right of yours. if you don't agree to him going abraod then u may seek seperation if u want and live a good life i dont find any logic and fairness in husband living abroad for FOREVER and wife spending rest of her life living alone. you'd be better off without him. things would make somesense if he 's going for a particular time period like a year or two or agrees to call you once he is settled or make an arrangement for you to live there for atleast 6 months with him. other than that i dont think you shd put yourself in any misery of living your life alone for your remaining life.