Have you ever known someone for ages only to realize you didn't know them at all?

I’ve had this feeling before it was after an eight year relationship. When we broke up I realized she was almost like a stranger to me.

I have it again now. A nine year Net relationship has finally ended. Looking back I guess when he met me I had it all. I was a different person. Well off, younger, fun, healthy also sexy. Of late I guess I became a burden to him. Depressing and sickly. So maybe after all I wasn’t what he really wanted. I’m glad though as I nearly moved thousands of miles to be with him. I realize I didn’t know him at all. I doubt even his family knew of my existance. The worse part is that he didn’t have the guts to be honest enough to break it off. He just messaged me less and less I didn’t know him as I thought I did. Has any one felt that feeling before?