I don't know how to have my own life

I was with my ex for 6 years and we had an entire life together. We lived with his family, hung out mostly with his friends (I spent time with mine be he never really went), him and spent time together. I did my own things like go to the gym and see friends occasionally. What I have realized is I was mostly was in his bubble. It wasn't forced but it's just how things happened. His family was my family. Now that we aren't together I feel like he is going on like everything is normal but for me everything is completely different because I'm out of "his" world. Idk how to have my own life and it sounds so sad. He wasn't controlling or anything like that so I don't want it to come off like that. We were about to buy a home so obviously I took my name off of the mortgage and now he lives there. So the biggest changes in his life is I'm gone, new home and I have the dog