I´m sorry some one disappointed you!
The only thing I know, if you don´t have real approaching experiences outside the www, you probably are somewhat vulnerable and, if you have had them (which is best and voids idealizations) you probably have seen people fade off like seasons in life. If that happend, he probably had his BBD (a person came he thought better than you, and left).
Just thanks GOD he left before being married or having childrens, just a vague idea to see the possitive inside the emptiness a person might feel when being left (as another type of rejection).