Ex husband hacking my gmail?

you need to get ahold of google and let them know what is going on and what you do about it because you need to find out if its really him or its not someone else you should be able to let google know wherte he is logging in from cause is conscidered in a way stalking google could probably delete the device plus it also depends what he is looking at you could also call the authorities he probably sits and watches you change your passwords and your security questions