I guess I had a similar situation round 2008...already had 360, bought a PS3 for Killzone 2...decided partly that I just didn't like owning two consoles, felt too disorganized and too much backlog, sold it. Course, recently my brother became my roomate, and he has a PS3 that is basically mine since he never uses it, and I've done ok with that (I mostly stick to 360 anyway, dislike PS3 controller).
See all my life I've strictly owned one console at a time. Always (even went back and forth between SNES and Genesis, even had a Jaguar as my sole console, sold it for a 32X, etc!. When I was a kid it was out of necessity, I had to sell one to finance getting another. But today now that I can afford multiple consoles, I've found I dont enjoy it, one is just simpler.
The worst was being a sole console owner when long droughts came along, like the Jaguar, the N64 (worst ever for droughts imo, if only cause at least I realized the Jaguar mistake quickly and didn't stick with it, and even the Xbox 1 really)
That said, I've begun to fight against the whole backlog thing weighing on my mind. It can become quite OCD like. If I dont want to play something, I try to not play it, and try to control my mind such that I dont feel obligated too.