Is this woman a cheater? A loser? or just new to me?

You are the one who has the issue with relationships not her...you need to get yourself sorted or she will dump you..i left my b/f for these same reasons and he wont get me back...my love was never exonerated...and neither will hers if you carry on like this...once bitten its not true you are twice shy..as one bad experience does not cancel out a few good ones..and if every relationship you had had was bad/abusive then you would need to really distrust...