Always look out for numero uno...I think when you're introverted, been single for a very long time, and used to being alone and moving at your own speed, when you finally meet someone who is worth your time it can still be difficult managing the "me" vs. us. Being alone can make you selfish, for better or worse so adding someone to the mix that you have to consider in some of your decisions can be a challenge.
Just something I've been thinking about