Character: As is the case with a lot of these Q&As, the answer is, “It depends.” Now, you don’t want to throw around “it depends” to everything. Sometimes you want to stamp your foot down, and sometimes you need to be flexible and see nuance. I think a gambling problem really weighs heavily on the character dimension, in particular the following:
With regards to trust, does their gambling problem lead to trust issues in the relationship? Does your partner sneak off and not tell you where they’re going? Do they lie about their losses and winnings? If they do this regularly and in a way that pisses you off, then unless they’re stellar in every other character trait, you should not be with them. For most people, trust is the most important character trait.
Responsibility is another obvious aspect to the gambling problem. Is your partner a high-functioning gambler? In other words, can they gamble but still keep their job, keep their house, and keep their car? Can they stay healthy while being a gambler (casinos are smoke-filled places that make you sit for hours on end and warp your sense of time)? It’s ultimately their money, and if they can keep their wits about them throughout the ups and downs then maybe you want to let it slide. But if it causes them to take poor care of themselves or if they miss appointments or dates with you because of their addiction, then this is definitely a major mark against them.
Now, it’s debatable whether or not gambling is a chemical addiction. It’s chemical in the sense that there’s a chemical process that happens in any addict’s brain that is similar to those experiments with rats that keep hitting levers for cocaine or heroin. But it’s not chemical in the same sense as drugs are, since slot machines are just that: machines. Thus, your partner is more responsible for their addiction than they would be if they were addicted to drugs.
If you are properly communicating in your relationship, your partner should get the clue right away that you disapprove of their gambling, and so the question is, what do they do with this? Does it make them want to course correct and become a more responsible person? If so, then their responsibility character trait is more dependent on the context of a relationship boosting them. If not, then their responsibility issues will plague you down the road, when you’re having hard kitchen table conversations about where all the money went. Even if you’re not thinking that far in advance, irresponsible people are not dependable, and that’s part of why you got in a relationship in the first place, so that you can have someone you can depend on.
There is also some bearing on respect issues. If your partner knows you disagree with their gambling problem, but doesn’t respect your opinion, then that’s a bad sign. You have to be able to communicate negative feedback to your partner, and not have them constantly threatening you with blowback. So it’s important to not only watch what they do with their gambling, but also how they talk to you about it. Is it, “Honey, I know, I’m trying,” or is it more like, “Whatever, you’re one to talk. It’s fucking hard, I’m fucking trying, leave me alone. It’s my damn money!”
Chemistry: There’s also some chemistry questions. If you think gambling is stupid, it should turn you off if your partner gambles all the time. On the other hand, you might think it’s hot to hold onto your partner’s shoulder while they throw dice on a craps table. Or maybe you enjoy all the comped rooms in Vegas. The risk and thrill of it all is perhaps exciting to you. If so, great, you’re following your bliss. But do not let that obscure the character implications mentioned above. They will come back to bite you in ways you don’t foresee yet.