It's important to take responsibility for our actions and their consequences. If you treated someone poorly for almost two years, it's understandable that they might have moved on quickly once you expressed that you didn't want a girlfriend. People have their limits, and if they feel mistreated or not valued in a relationship, they may decide to end it and seek happiness elsewhere.
Feeling guilty about how you treated someone is a natural response when reflecting on past behavior. It can be a valuable opportunity for self-growth and learning to treat others with more kindness and respect in the future. Acknowledging your past mistakes and making efforts to change and improve as a person is crucial.
As for blaming her for moving on quickly, it's essential to recognize that everyone has the right to make their own decisions and pursue their happiness. People have different coping mechanisms, and the speed at which they move on after a breakup can vary greatly from person to person. It's not fair to blame her for seeking a healthier and happier relationship after experiencing a difficult one with you.
Instead of placing blame, focus on learning from your past mistakes, making amends if possible, and striving to be a better person in your future interactions and relationships. This way, you can grow as an individual and build healthier connections with others. If you find it challenging to cope with the situation or your emotions, seeking support from friends, family, or a counselor can be beneficial.