No I don't believe you are a martyr. I believe that you did what most humans do. He was showing his 'nicer' side, which gave you 'hope' that maybe just maybe things could change. That my dear is being HUMAN. We (at least most humans) seem to have 'hope' that a person can change. Just because some don't does not make us martyrs.
So, please stop beating yourself up. When we are dealing with someone we care about we, as humans, usually bend over backward to give them every chance possible. That does not make us martyrs that makes us HUMAN. Only when we have been 'knocked' down (literally and/or physically) enough times do we finally stand up and say ENOUGH. NO MORE. You are now standing up and say NO MORE, NEVER AGAIN.
I say ......................................... GOOD FOR YOU!!!!!!!
Go to Court, tell them what he did in a matter of fact way, just as if you were reciting a recipe. If you break down and cry, because you are traumatized that is perfectly natural and believe it or not 'normal.' Tell the truth, don't look at him, look at the attorney asking the questions or at the person who comes with you.
You will do fine. And, you will feel better, getting it out to someone (the judge) who can actually do something about it.
Know that we will be with you in 'spirit'.
Love and hugs,