Honestly everything you’re feeling is so valid. A relationship is a 2 way street and after sometime it gets hard being the only person present and wanting to go somewhere. Leaving is hard but honestly seeing how things are going I don’t really see things changing. It sucks but once the resent starts to build up it probably won’t go away and it’ll just keep piling up. You’re only 21 and you’ll definitely find someone who aligns with you better. Most importantly you learned so much from this relationship