I was in a similar dynamic in previous relationships. Most of my boyfriends were way more sociable than I was. it came so easily to them that I always seemed to be the weird one because I mostly liked being alone. It's difficult, particularly because comparing ourselves to other people can become unhealthy for everyone involved.

Ways to make me less lonely usually include being mindful of the small things we take for granted. Going to a nice restaurant, for example, and taking a long time to eat so you can savor the taste of it. Sitting in the park and listening to the birds or watching squirrels play. These are things we often overlook when we're around other people, and when we're alone somewhere along the way you might appreciate that there are these outer mechanisms at play, simply existing like you are.

Another way to feel less lonely is to find activities oriented for one person. Writing, drawing, exercise, reading a book, etc.