Married with a 'man cave', I don't think so. Best you spend the first couple of years together without creating your 'get away' space. Any woman, assuming 'sound' mind, would be crazy to buy into your plan. Wait until you both are ready to buy your own place, with room for a paid for addition. By that time you will both know what 'married' is all about. So, come to your senses quickly, or your relationship is doomed.
Anyone ever think about building a dedicated room?
It looks like sometime in the future, when my girlfriend and I get married, that I'll be moving in to her place. She's currently living in a guest apartment in a house with plenty of space in the back yard. I've been toying with the idea of having a 15' x 25' (dimensions can be smaller) "shed" out back. I figured I could have it built with super thick walls and lots of insulation so that I could just use a space heater in the winter, and in the summer I guess I could open the doors and blow in some fresh air. All I would need would be some good electrical outlets and I'd be good, right? Have any of you thought about doing something similar and if so, what obstacles would I have? I don't even know if something like this would be worth it.