Perhaps the best advice you can give someone about having a relationship with a married man is telling her not to even start. However, that may not be practical for all women. As my friend Jenna* told me, "You can't help who you fall in love with. The love of your life just might be a married man."

Being part of any couple can be challenging and unpredictable, as we all know. But when the man with whom you're involved is part of another couple, someone else's husband, then the challenge and unpredictability can make your life a messy, unhappy waiting game that you will rarely win.

The woman who is in love with a married man lives a life that, for the most part, is shrouded in secrecy. Her close circle of friends might know about her affair, but she really cannot let anyone else, such as colleagues or her family, know. She is alone most of the time and spends it waiting: waiting for her married lover to call, to come meet her, to share some precious time together. She is not his wife, she is not mother to his children, she is not his parents' daughter-in-law. Her chance for happiness hinges on a future that is highly uncertain, to say the least.

Your own survival is crucial, and if you do happen to fall in love with a married man, there are several hard truths you need to know.

1. The needs of the many (namely, his family) will always outweigh your needs.
His family will always come first, and that includes his wife. Simply because he talks in a negative way about his marriage doesn't mean that his obligations to his wife are any less important to him. Whether or not they have children is a moot point; he will always feel as if he has to be a husband to her and take care of the marriage, whether he truly loves her or not. Their life together includes friendships and a social network that is shared and comfortable for him. He won't risk losing that.

2. His life with you is secret and always will be.
No matter how much you may want to walk in the sunshine with him and have him openly acknowledge his love for you, it won't happen. While he is more than willing to be your lover and to bring you gifts, he is not about to have you meet his friends and risk having his family find out about you.

3. No matter how nice a guy he is, you are a temporary diversion for him.
This is not an easy statement to comprehend. It's emotionally painful. Unfortunately it is true. The beginning of an affair is romantic and naughty at the same time. Planning to be together becomes a fascinating game and is thrilling to say the least. Stealing hours from work or home to have sex is exciting, and you may mistake his libido-driven passion for undying love. Don't. The game soon becomes a chore for him, and romantic interludes are just one more thing he "has to do."