Well the beautiful thing about your soon to be x is that he doesn’t have to deal with psychoactive drugs. He might celebrate that fact and let you decide what is best for you. You can always just tell him that his advice is unsolicited. Anytime he brings it up in any way, shape or form just hold up your hand and say...ah ah Unsolicited.

It might infuriate him but be immensely satisfying for you.