Heard back from an ex... after three years without contact!!!

Briefly, the story is that about three years ago I had a really bad experience that completely changed the way I view love and relationships.
I had a man in my life that I loved deeply. We spent all of our time together. All kinds of activities, hiking, dining, cinema, cooking together, studying at the library, going to cultural events, etc. He was very generous, caring, loving and open. I also thought he was genuine. That was the old naive me who thought that this man was the real thing. We were in the same city for over two years and he unfortunately had to move away to start a job in his field.
We continued a long distance relationship and were making plans for me to move and join him. We visited each other every month or so and spoke on the phone daily. But one day, he didn't return my calls. He just disappeared, without any explanation without a goodbye, nothing. I was terribly heartbroken and extremely hurt that he could just leave like that. It also left me feeling like less of a person as I felt I had been used and abused. The little bit of the self-esteem that I had was crushed. Since them I have avoided men's attention and distrust their intentions. 
Until last Thursday. I received a hello emoticon from him on my Facebook page. I had unfriended him a long time ago but I guess he still had old messages in his box that he could use to get in touch with me. I was a little shocked and looked at the message in disbelief. Mind you it's a very small gesture on his part nothing to get excited about. But still, it made me feel whole again. Like a huge part of me that was stolen was brought back. If I never hear from him again, I really don't care anymore. I just feel good again about myself and feel that I can trust again. I can't explain it, but that message has sort of brought me back to living and believing again.