Some keys to keeping peace at home:
1. Flip enough bikes that the returns on flipping exceeds what you are keeping ("Its not a collection, its an investment!!!").
2. When you decide to keep a bike (addition to the fleet), have it replace something in the fleet to keep the fleet size managable. It was really easy for me to retire (flip) the Schwinn Criss Cross I had when I picked up my Colnago. I have upgraded all the bikes in my keeper fleet a couple of times each in the last year. As long as one moves out when one moves in, you are OK.
3. Buy some bikes that are NOT your size. This makes the flip decision much easier. Its a lot easier to let something go that does not fit.