Any love spells are a tricky and unethical (in my opinion) thing. The casting of these sort of spells includes the act of taking away another persons' free will, so even if it does work, you won't know if the feelings they have for you are real or fake. Also, how would you feel if someone you didn't like made you have feelings for them and you didn't understand why? A better way to go is by making an "influence" spell, one which will convince them to notice you and notice their feelings toward you. Spend more time around them, as well, and soon they will begin to subconscious think about the qualities that would make you a good partner to be in a relationship with. And yes,I would suggest breaking up with the woman you are already with if you want to have an honest relationship if you are really dedicated to the other girl.