The relationship lasted 1,5 years. For the last half year, we were doing poorly and I didn't really know why. I didn't see her being as unhappy as she was either, because for some reason I 'forgot' to pay attention. In return I was under some stress myself because she closed herself off from me a bit and things spiraled down from there leading to the break up.
The biggest problems I had were expressing my feelings and even more understanding hers, seeing that she was unhappy with certain stuff (stuff I could've easely changed).
Why do I only recognize these things right now? We had a talk a few days ago and she was really relieved to know I do know what my mistakes were.