I agree that it's vital you find some "quality-time" with yourself. There's only so much you can deal with in anyone day.
Personally, I spend a lot of time either in my bedroom, sat outside under a tree. Usually clutching my guitar and strumming a few things. Not really trying to practise anything, but seeing what comes up. It's nice to be able to relax and let your mind wander, without having to worry about ignoring someone, or having to pay attention at all. I think it gives you some time just to think things through. I'd recommend to everyone you find just ten minutes a day at least (definately more!) to yourself were you can just get away from it all.
Having said all that - it is healthy to spend time with others. Particular if they're people who you enjoy being with and feel comfortable around. Certain people can relax you just as much as sitting under a tree with your guitar.
It's all about balance.