I [28 M] am tired of my relationship with my [23 F] 6years,love her but too anxious to end it, but its hurting to keep it going

background info: -city we live in is neither of our hometown, I work here and she studied here. but she recently ended her studies and is on study leave doing her dissertation whilst staying in my appartment

• we have been together for 6 years , I love her but I just don't see a future for us, we are completely different and have virtually 0 overlap of interests. -we have had 'time apart' from each other where we had sex with other people,

so basically I really love my girlfriend, but I don't see a future for us being together. she stays in my house and rarely goes out and it feels like she is demanding all my time, but I like to have my own free time to focus on my hobbies and stuff but I cant, she has said that in the future she wants children, something I have no intention of ever having (I know this might be trivial, or people say "you'll change your mind", but I have never wanted children since I can remember) Apart from reading my girlfriend doesn't really have any hobbies, she does some teaching at the weekend but that is really it. but she is at home 95% of the time and tries to control what I do to some degrees, I am allowed to do stuff I want but I feel kind guilty about doing it, for example meeting friends in the evening or something.

I have anxiety and find it hard to talk to her about problems or issues, and its only really when she gets upset at something that I end up 'spilling my guts' and telling her my problems. I have felt like I want the relationship to end for a while now, maybe 2-3 years but I haven't ended up and I feel anxious just thinking about it but I believe it would be better for in the long run to end this relationship despite there being no problems besides us being completely different people. I don't know what I want from the future, but I just feel it would be better for us in the long run just to be friends and see other people.

tl;dr: been with g/f for 6 years don't see future for us, no common interests and need to think of myself. I am happy in the relationship but unhappy at the same time, and I think we need to split up or something

I haven't the slightest idea even how to talk to her about this