IS IT COOL TO BE A MISTRESS?????
Cuz they're lonely.
It's a shortage on men.
They have no loyalty to other women.
She think he loves her more than he love his wife.
For some sick reason she believe he's gonna leave his wife.
Her ego is boosted so high cuz she's sleeping with someone elses HUSBAND.
Some how you always seem to forget, if he'll cheat on his wife he'll do it to you.

I think in cases like this people should consider some of the practices of the 3rd World or Islamic people such as polygamy. At least this way the first wife will have a her status as the first wife which brings more respect and clout. The other wives can still have a piece of the man.