I know everyone is blaming Nikki for bringing David Chow into their lives, but she was not the person that brought David here, remember he came into the picture when Carmen was killed, he was terrorizing Dru and then he stayed and was working for Victor through Glanville (sp?) Global, then he was Jack's campaign manager and then he became hers. Yes Nikki fell in love with him and he had a gambling problem but being that she had dealt with her own alcohol problem she wanted to help him. I don't blame her at all, sometimes love is blind.
The only thing she did wrong was mess around with David before she divorced Victor, but remember Victor left her to deal with Nicholas's plane crash and he wouldn't support her during her campaign. And besides how many times has Victor messed around on her, I don't think I can count that high.