Many people obey their girl friends more than anyone else.
What if their girl friend insists you to stop gambling

Will you Stop

Why will anyone become a slave to another because you want to satisfy an urge of a girl? No one has to obey anyone against their own standard. If you want to stop gambling, do it because gambling affects you and not because someone is forcing you to.
Often times we never realized something until someone forces us to realize it. A gambling addict will never admit he is addicted unless someone had clearly pointed it out. In this case, if your girl asked you to stop gambling, or even force you to stop, threatening you a break up if you don't listen, simply because she is concerned for you. She shouldn't have a problem with your gambling activities if she isn't concerned about the possibility of gambling addiction.
Even if someone already knows that you are addicted and ask you to stop, you will likely disagree on them and still continue gambling. The person that are out of control on their selves deserve to be leaved by their girlfriends or even their friends but I don't think their family will do the same thing.
Maybe they will realize soon that they are wrong and will now change for the better once they lost the people that are important for them. Indeed it's a selfish act if the guy will spend more time gambling more than his girl. If that was the case then he better be single because he can still be happy anyway with the company of gambling.