No reason to worry as there are a lot of gay people visiting Marrakech.
I staid at Riad Magellan back in December last year. I staid there with my partner. 2 men sharing room and bed and there was absolutely no problem.
The Riad Magellan is a very small Riad in the Heart of La Medina. We had very good time staying there. The owner and the staff are all very warm welcoming and will give you great recommendations to go around.
www.riadmagellan.com