Actually I think his suggestion is a good one, and does address your question. The way to seek, find (and keep) a girlfriend has more to do with who you are than what you do affirmatively. So your girlfriend probably decided you two were not a good match because of who you are. In my experience, spending a bit of time looking at yourself pays off 100 fold when it comes to finding people who want to spend time with you.
In any case, good luck and be patient. Good things will come.