You came to the right place man, we're all here with different goals, but the same reason. Take the first week to experiment (don't overdo yourself) and get a routine going. And after that, there's no stopping you. I don't know if its allowed on this forum so I won't name any brands, but I suggest buying some supplements such as [words=http://www.mattersofsize.com/join-now.html]penis enlargement pills[/words]. Taking them by itself won't help, but with the exercises they do.
And don't forget to take down your measurements. I started as 5.25 inch erect penis, and in three weeks I am already 5.5 inch and sometimes when I have a super boner, it is almost 5.75. I have a relatively small penis so I guess the gains were quicker? Who knows, perhaps you will have my luck.
In reality I'm still a newbie, but once you get started man, ain't no stopping you. My girlfriend broke up with me for the same reason. I can guarantee in 6-9 months time though when she sees my new body (I've been working out like fuck...so ripped like never before) and my new snake unleashed, she'll be wanting me back. But why settle with an ex? There's a world of girls out there.
Don't let her destroy your ego man. Be the stronger person, do what you gotta do, and live to see happier days.
Peace and love.
-gunz