I read this book in the early 2010s (maybe 2012?) in the UK. I believe I bought it new in hardback from a bookshop so it was newly released at the time.
It opens and closes in a train station with a miniature train going round (I think). Male protagonist who had dropped out of society and lived on an island. It is unclear if this is Augmented Reality, referred to as AR throughout the book. His male friend who is married visits him and as I recall they begin an affair, though again this may not be reality.
The house he grew up in was also a home for rehabilitating soldiers; his father invents or modifies AR equipment for them.
I believe his mother is murdered, possibly by one of the traumatised soldiers. But this isn't really talked about. He was a teenager at the time. I think the story is told through flash backs.
That is all I can remember with some degree of confidence.