His wife died, a few weeks later he looked for me... "his best friend".. but????!!!?

we are friends for 5 years, we were co workers int eh same company and we shared everything our lifes, our lunch time, all business trips, we became very close buddies.. we enjoyed doing things together... all of the sudden his wifes ped after a long illness which he was carrying on with for 2 years.... during this time i was his emotional support, he cried and i cried with him and a few weeks later we started to feel in need to be closer... we talked about how our feelings were changing and how we were feeling attracted, we decided to move one step forward and go on a trip with his small 3 year old daughter... that trip was wonderful, i saw him happy, relaxed and smiling for the first time in years (since he also sufferd his wife illness) we made love that night and it was wonderful... having my best friend a confident with me... and he felt happy too... the next few days he told me he was falling in love with me... and that he was feeling guilty to be happy... all of the sudden he dissapeared. we are still in contact, he emails me, he msn me, but he is not romantic anymore, and when i asked him why is is distanced from the relationship he wanted to have.. he told me that he felt weird, that things were too fast, and that time will tell what results between us.... i am screaming with this... is this something yo do to your best friend, is he only confused and needs time? i have to tell that there were other women going after him to catch him becaus he is a very nice guy, cute, and good person.... but he rejected these woman,he wanted to be with me... his best friend... please help me what is going on... i hope i get responses from men, i expect sensitive and considerate answers... thank you