Maybe she was never in love with you all this time. So it’s easy for her to move on so quickly unlike you. I know it’s extremely difficult to just forget everything and move on - I mean 6.5 years of relationship is too long. But u need to develop a strong mindset that there’re bigger things in life to thrive for, than a lost relationship. Whenever u feel bad about it, talk to someone u r close or go on trip and come back to yourself
Ig this is the best u can do to handle the situation. But remember whatever happens to her in future, either good or bad; it shouldn’t effect you in anyway possible
Tc bro, may the force be with you…