Which one am I to him

This is a yaoi and also some other relationships and this is my first story so please be kind yes it may have different emotions at the time but it's one for a forbidden relationship when they accidentally fall in love for each other. The young prince was a fiancé for the young vampire lord but he fell in love helping this random guy off the street. The vampire is very needy bossy and never gives up on his fight for what ever reason he is one bad dude to mess with.
What will happen if the vampire finds out what his wife was doing? What will happen to the forbidden relationship? And how will we know if the vampire lord will accidentally kill the one he loves?