k, love spells work. you can cast as many as you want. all of them working comes down to how much energy and focus you have for each one.
this being said, be careful what you wish for. it can backfire, but more importantly, casting a spell to effect someones free will is considered black magic 'as it harm none, do what thou wilt' [if you believe in the reed anyway] you are forcing someone to feel the same as you, you are doing harm, and the rule of three will come back to haunt you.
while your intentions are good, and i understand you must be sad, it's far better to let him choose on his own. yes, there are some love spells that if the person finds out will turn deep love into deep hatred, but think about this; in 10 years [say the spell worked and you're together] you'll still have to live knowing that he might love you for you, but he probably loves you because of the spells.
it's your life, do what you want, just think about it. if you do continue on with casting, i would suggest holding off until the new moon because the current waning phase works better to take things away [weight, unwanted guests, bad habits]