wow, this is too complicated for a single human heart to decide... but i'd say, go for the one who you think and feel is right for you... if you think the love of your EX is more than your current BF, given that you're still inlove with the EX, then the answer is clearly THE EX...
(singing) ...are you gonna stay with the one who loves you? or are you going back to the one you love...?