Well to share my experience, which may be helpful or not, but never the less. I agree with the above post that their upbringing, and also the rest of their charts. You may want to look into that, for a better understanding. I was with a Libra for 4yrs, he was 22 I was 16yr, ha! (Sarcastic)
He cheated on me many times, never would tell me but I knew in my gut. First was a friend at school she was15. Than I am sure a few others, up until he I found his cousin and him wrapped on another, last straw was cheating on me with his "friend" and getting her pregnant. We had a child that he hasn't seen since by his choice. I remember he went and stayed out of town, for school and his roommate was another girl. This all drove me nuts, I was young and dumb. Out of all 7 Libras I have met, I will say 2 were faithful from what I know, those 2 also knew what they wanted in life and love their families greatly as for the others they are constantly wanting other avenues, Tattooist, than paramedic, than Mechanic, and so on. My opinion is that maybe you are dating other men, because you your self don't want to settle for what you sub-consciously already know....................I felt the same way, with my Libra, I always felt like he was someone I should honor, and why did I have such low self esteem, thinking he was cheating, and he would say that and, if I wanted others girls would I be with you? What I learned after all of those years, is to trust my gut instincts. I believe it is your soul guiding you. There are more reasons than your "mishaps" of why this hasn't worked. I think it too would be beneficial to lay it all out, and go with what you feel inside. You won't be wrong, and even if you never know, deep down you will. You don't have to jump off a bridge, to know it's going to hurt.
Best of luck!