I am an introvert. No matter how wonderful you are, you wear me out. We can have a fabulous time together, but I am still going to need a break from you eventually. It took my spouse a long time to learn not to take this personally. Even the most wonderful people (like my husband) and the most enjoyable times (typically involving beer or wine and fabulous food) deplete me, and I need to be alone in order to refuel.
In spite of this, I learned a crucial lesson several years ago: I am a better human being having a network of people that I am close with, vulnerable with, honest with. While it felt counterintuitive at first, I knew it was true. Alone, I am limited to my perspective and prone to self-centeredness. With others, my understanding is broadened and my capacity to love increases.
If you are fortunate to have people around you who are willing to do the hard work of building, strengthening, growing your relationship, then do your best to keep those people in your life. Too often we let go because it gets to be too much work. Granted, there are times that we need to let go. But I wonder how often we let go too fast, only to then later wonder if we let go too soon.
I still need my alone time. I love going to a movie or dinner by myself. But I also need my together time. Party of one? Yes. Party of more? Most definitely.