Or you could move on.
You say that you, would take him back, you think...
You are willing to destory someone elses relationship, when you are not even sure what you want.
The best thing to do is take a step back and view the situation from afar, if he is happy and you are not, then maybe it is you that needs to move on and find your own happiness, away from him. Not every partnership is meant to be and this could lead you on to bigger and better things. A spell won't get you what you want.