I Am Worthless

am a complete failure, people tell me its not my fault but want do they know. See I am 39 years old and I really don't know what love is. I will start from the beginning I love my dad but he beat me because he was unhappy with my mom, my mom had a hard life and seem to take it out on me. I wanted so much for someone to love me that I was willing to do anything to find love. And what did that get me? Everyone I loved and tired to give my love too, left me or used me or abused me in one way or the other. when I was 17 I moved 100 miles away from home to take care of my grandmother after my grandfather passed away, thinking to myself that I finally found some reason for my life. Grandpa was gone and grandma needed someone to help her, but she was standoffish and tried to handle everything by herself. "She needed know one so she thought" . I finally found someone that really wanted me we will call him E. And after two weeks of us knowing each other he told me that he wanted to marry me. He said he was looking for me his whole life. And like a stupid B____ I believe him. So we married after only 3 months. I was amazed at this, someone that loved me and thought I was something special. We were only together 2 years and expecting our 1st son when he decided I wasn't Worth s--- . when We were only married 3 years And I was pageant with our twins he was sleeping with my 15 year old sister while I was in and out of the hospital trying to keep our twins in long enough for them to be healthy. but i request since then He has had so many affairs that I'm afraid to count. We have been together for 21 years now, and within the 21 years he has sleeped with my sister, my sister-in-law, my friend, and an mutual friend of ours, and now after all this our child now age 19 and 1/2 thinks that there is no relationship that is worth a risk, our 17 year old twin son thinks that love is all about how many girls he can go to bed with, and our 17 year old girl twin thinks that a guy can only love them if the guy lays down and let her walk all over him. So yea I m BIG FAILURE I FAIL everyone I love. And don't even know why God keeps me around.