Hi, I think it is a common problem with a lot of couples who've been together for a long time.
I think you need to find your own space, going out with your separate friends, etc. Don't just stay together all the time.
Or, you can try to make some crafts, like ship models, flowers, balloon sculptures together. I tried this with my man and it works. You can try to learn things that she loves to do very much, or vice versa. This can help foster your commonality, so that you'll find it even harder to separate Bring in some fresh air and you'll feel better.