Am I a bad wife??

I had a bad experience when I was younger and I do not like having see very often. My husband and I have been together almost 3 years and I just now told him about 4 months ago about what happened to me. He wants to have sex all the time and I very seldom feel the want or need to. I have sex with him about twice a week but I get mad when he tries all the time. Am I a bad wife for not wanting to pleasure my husband all the time?..