...they may have lived a 'lie' long before they became your closest friend... and having to keep it up is very, very hard I'm sure. So why don't you suggest that you 'percieve' there is another 'story' that they are not telling. Something that you feel they are 'leaving out'. Sometimes folks will only open up if they feel you've 'been there' too, or if you can broach the subject in a compassionate way, not a judgmental way (hard to do!). After all, who hasn't told lies.. a good place to start the conversation.
Angelwings

If the grass is greener on the other side, its sure the water bill is higher !