You have achieved the most important objective for every writer: You caught my interest. I wanted to know more. It's not exactly that you teased, but you did open a door and invite me (the reader) to have a look. You show restraint in not asking the other about 'his' past. With that restraint, you create a kind of tension. The less you want to know, the more we want to know.

In the end I (the reader) feel a bit frustrated. While you choose not to know more, we don't make that choice. We persevere through the story because we want to know.

What you do here is totally legitimate. You give us all the clues and explain why we will not know more. And yet... we want to know :))

Great writing. I did, however want to know a little more about the mystery man--at least something about his relationship to you.