I posted this nearly two years ago. Nothing has changed. Everything still works and no-one has a clue. I'll leave you to decide whether you think it is a good idea or not:
I have name changed. I do not want what I am about to say associated with my regular name.
I am unhappily married. Desperately unhappy.
DH has NO idea. DD & DSD have NO idea.
I smile, I play, I say I Love you, I have sex (and pretend to enjoy it). I ensure that DD sees me cuddle her father at least once a week. I say things like "you should ask dad about that, he's really good at that sort of thing" to DSD, even though I dont believe what I am saying. Those girls have no reason to believe that I am not totally and happily in love with their father.
I decided to do this. I decided that their happiness was more important than my own, and I want them to believe that we are in a happy marriage. I do not want DD to see us divorce, I do not want DSD to have to go through it again.
2 years ago my marriage almost broke up. It was horrible. DH was awful, violent, threatening and abusive during that period. DD saw it and it really affected her. I decided then and there to stop arguing, to stop trying to get away. DH believes we worked through our problems and we do not have them any more. NO, I just decided to stop letting our problems bother me. Now I do not care what he does.
DH believes I am happy. I am not. I let him get away with anything he wants, and I smile about it. I will never divorce him, but in reality it would be easier if he died.
I may have resigned myself to this life for the next 50 years - but it is a choice I have made for the children and I am happy with my choice.