She is a perfect wife, but clueless in bed

I have a beautiful wife (26) and we have been married for two years. She is a perfect mum and wife and does everything well. But she has one problem – she is flat in bed. She never seems interested in sex, has never initiated it and every time we are intimate, she expects me to do everything. She always remains stiff and quiet and I don’t think she has ever had an orgasm. The interesting thing is that she doesn’t seem bothered about the issue.

 I have tried to make the sexual experience better and more romantic, in vain. I feel frustrated and I am losing interest in her. I had been with several other women before I married her and the sex was great. I need your help urgently on this. I am ready to accept criticism if you think I am part of the problem. I just want our marriage to be as blissful as the others seem to be. {Mark}