Ah... this explains the 15 women you've been with and your reasons for questioning your girl about having 5 partners before you.
All I can say is that you will fall in love, then you'll fall out of love, or get hurt by them... then start the process all over again... until you've learned enough and have found someone you are compatible enough with to actually make a relationship work long term.
Till then, I'd suggest you pay attention, live for the moments while they last, and learn from all that you experience. Not much more you can do...
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen