Personally, I would have gone alone recently, but in the past, I would have asked him along. It's just personal choice, I guess, and my choices have changed. This getting a life really does work, and it may be good for you to get away alone. Have some time to think and work on things in your head. But, will this draw him closer to you? Will he be jealous or wondering where you are and what you are doing?
How about inviting some girlfriends along and having a really fun time that way instead. That may be the best of both worlds, you can make him wonder what you are up to while still having fun and not being in separate rooms.