As a couple, your stay should be fairly smooth, as there are many foreign couples who travel across Morocco together. However, if you are male and your partner is a female Moroccan citizen, you must note that you won’t be able to book a room together anywhere, unless you two are married.
Being gay in Morocco is sadly still an offense, so people usually just avoid displays of affection in public. There should be no problem, however, booking a room if you and your partner are the same gender.
While strolling through the narrow streets of the Fez medina, you will have to embrace the busy crowd coming and going, so be careful of anyone trying to put their hands where they’re not supposed to.