Deirdre and Monet are a lesbian couple who become arch rivals to Will and Grace's apartment flipping business in Season 6.
Deirdre is shown to be very possessive and controlling of Monet, controlling her caloric intake and chastising her for showing attraction towards men.
It is implied that Monet is in fact bisexual as evidenced by her lust for Will. Will takes advantage of this by seducing her in to sabotage her partnership with Deirdre. However, Deirdre forgives Monet, saying Will "is beautiful, like a female k.d lang." 
- It is implied that Deirdre once had an affair with Karen.
I'm sorry, I need food. I already burned off that Tic Tac. — Monet
- ↑ East Side Story