Probably the topic assumes that the gambler lose everything as in including the funds which they are both save. This is the common reason why married couple destroyed when the problem is due to gambling addiction.
Some people can’t stand already their partner once he already affected the family finances in general. No one will gonna have a problem if the gambler still earn or doesn’t loss since it’s still part of entertainment but I believe even can’t stand a husband/wife that spend too much in gambling to the point that your family savings is already at loss.
But that makes what I’m saying. It’s foolish for a partner to be all in love and happy when their other partner is winning all the gamble. But when he/she loses, the love is gone and you want a divorce. If it were me, I’d divorce her because it means that she never really loved me. When you love someone, you should be with them at their worst (especially if you were always with them at all the bright times).
The outcome of gambling is always about winning and losing, I understand what you mean here in that we have to look more at the idea of a "habit that has the potential to create bad situations", I understand that winning is possible and maybe even by a large amount but isn't losing also a possibility? Obviously, that means losing and winning are the outcome of gambling and losing is a situation that you will definitely experience at any time and even dominantly.
Everyone is happy with the name of victory or when they get a win, but if the partner can think wisely about the gambling habits of his partner then I think it should not be for him to feel too happy with the victory that his partner managed to achieve because of course they will think that defeat will definitely occur which may even be with a greater amount than the previous victory that his partner managed to get. So the point is that people who really love are those who are able to think about the good for their partners in the long run, so I am sure that if your partner is able to think rationally then he will definitely advise you to stop gambling even though you just got a big win.