This relationships sounds very rocky. A healthy relationship must be 50/50, where both partners put effort into each other. This applies to even basic friends. Without that, the relationship becomes one-sided, which is almost never worth the effort. \
The best advice I think I've heard is "Become the strongest version of yourself." It works because it applies to every arena of life. Relationships, skills, ideas, etc. You said that you are "boring, not very empathetic or sympathetic." You may be exaggerating, but if that's true, I would reflect on you and ask "How can I improve this or that about me?"
Basically, when it comes to getting a partner, don't ask yourself, "How do I get a good girlfriend?" Ask instead: "How do I become the kind of man women want to be around?"
As for her, I highly advise you cut the relationship. It does not sound like it is working out for you two. If you keep putting effort into a bad relationship, it may be distracting you from other, better relationships you don't know about yet.