The best you can probably do is to contact the company and request a goodwill adjustment. Since you paid it off, then they may grant one. It really just depends on their policies and the person you happen to get in touch with. If you search this forum for goodwill letters, you will find a lot of examples.
More than likely stuck. If there was an emergency or life threatning event in your life. Maybe. Turning over your finances to a girlfriend and trusting her was a mistake on your part. Yeah the trust should have been there but it wasnt. If you were married your wife would have probably not have done what the GF did because it would affect both your lives credit. Live and learn. Wont ask if you married the GF. TMI. But you could try a GW. Though that story with a creditor may not hold water. You can try and I'll say Good Luck!