.OMG!! My FRIEND found out that THE GUY SHE IS IN LOVE with is..........?

okay my friend, Cindy is so devistated. It's like her & this guy have been 'seeing' each other since last year & she has had with this guy & she was totally in love with him. well, one day she went to talk to him & he acted funny, well, when she asked what was up, he said he was married!!! She was devistated but, he keeps flirting with her & wanting her to still be there for him. He says that their marriage is having problems & that Cindy helps him get through it. He's so nice to her & she is so in love with him but, how can I help her see there is no future for them!! HELP!!!