First off, its really heartening to find that there are other people fitting the middle aged dad with a hobby mould!
My nature is all or nothing, and when I got the bug, I read everything i could, until my wife said, "look, you stay up night after night reading about watches, i would like to buy you a really special one for your birthday"
When i recieved it, I was talking about getting a sports model, then a dress watch.
My wife was only concerned that I space them out and enjoy them rather than getting everything at once (I did this when I collected guitars, and i tell you, I got addicted real bad - now I am down to 5 guitars that I really enjoy)
My family do not understand why I want to buy more, but apart from the occasional question, its accepted.
The other factor I think, is motive.
If I buy a fake Rolex so I can impress people, then thats one thing, but if I buy a watch because I genuinely love the look and the fact that I can buy a beautiful mechanical chronometer for a fraction of the price that most people have to pay, while learning about its intricies then thats another reason entirely.
I love this hobby, but if it becomes an obsession, and I collect a watch i do not intend to wear, then I give it away and take up something else!!