I believe I also read that he refuses to do nude or overtly sexual scenes because he feels it's disrespectful to his wife.
I have read that as well. But, so does Denzel Washington (think about it, have you ever seen Denzel even "kiss" a woman on screen? Not very often.), and it doesn't seem to have hurt his career at all.
It really irritates me that an an actor with the body of work that Caviezel posses, can't get any of the bigger, more coveted roles in Hollywood. There is a Hollywood "blacklist" for conservative minded actors and this is just added proof.