Does absence really make the heart grow fonder?

Two weeks ago, my boyfriend (fiance) of 4 1/2 years called off our September 2011 wedding and said he wanted to just be friends and have his space. I knew we had our ups and downs over the past few months regarding career/life/wedding decisions, and I think that postponing the wedding would have been a better alternative to canceling completely. Is it possible that he just wants to do his own thing for awhile and he'll come back to me? He told me he wasn't interested in dating other girls he just wanted to experience new things and be on his own for awhile. Everyone tells me to just "give it time," how much time is enough? I love him and it kills me to not have him. Is it true that absence makes the heart grow fonder?