What should I do? Im so confused :(?

I have been with my fiance for 2year, we are just about to finish building our first house which is in both our names, just bought a car together as well, in both our names (but its mine), if we split legality wouldnt be an issue, he comes from a great family and he is a great person and will do anything for me, he wanted to get married as soon as, we set the date for early next year but I got scared and we (heatedly) discussed it and its undated now. My issue is that I do know that I love him dearly, but I am unsure if I am in love with him and that I want to spend the rest of my life with him, we not as physical in all ways as we use to be and I dont feel as attracted to him as much either, and he always tells me how he would be miserable and lost with out me, but I dont feel that way if we wernt together thou, and i dont take him for granted either. I just dont know what to do? Please any advice would help. Thanks