If you haven't read this ones already:
•Eternal contract : Fantasy, Historical, Reincarnation, yaoi (In my opinion, Eternal Contract is the most similar.)
•KOUGUU NO OMEGA : manga, fantasy, age gap, shounen ai (The relationship is based on respect and they'll develop a romantic relationship just after both of them are adults.)
•TWO EMPIRES, THE SLAVE OF THE EMPIRE : Fantasy, age gap, yaoi (the age gap is actually physical. The leads met before, but one of them died and reincarnated with the memories of the previous life. This one is a bit shady and I don't really like it. The storyline makes it worth something)
•See You My King : Fantasy, historical, shounen ai
•HOW TO BE THE CHOSEN ONE : historical, fantasy, yaoi, harem (I haven't read much of this, but I'm sure the MC is a pervert, so if you're gonna pick this, expects weird stuff)
I also know some stories that don't match exactly with what you want, but you might like them:
•Murderer Llewellyn’S Enchanting Dinner Invitation - Not fantasy, but a historical, mystery, shounen ai
•Crush and burn - is fantasy, historical, yaoi (ig), but it has vampires
•Coyote - manga,supernatural, historical, yaoi ( expect a coyote)
