If they cannot fix that problem and don't talk about it. The relationship is at risk and likely to get separated. But even if the other one is a gambler, they can have a setup wherein the gambler can continue to do it but with limit. Everything can be done in talks if they have to do it. For as long as they understand each other and there's a limit to how much one can gamble to, it should work fine.
Yeah I agree, proper communication might prevent them to seperate as long as there's mutual understanding between them, gambling may treat as part of social activities or something that can be enjoyed if treated correctly, though similar to what the post above mentioned it can be a reason of divorced if there's no open communication and both financial and mental aspects are already been compromised.
That is why it is important to have a consistent communication with the partners. They will understand why people gamble and they will see that you as a gambler has been consistent and responsible. You know your limitations and you're not the others that are irresponsible. That's the reason why it's best to talk with it as usual and if there is some misunderstanding that keeps on happening, always start from the beginning and have it on the seat and talk about it. There is always a solution when the partners are consistent with each other and keeps on communicating, not that they're going sulk just because they are not given the favor. Not a single good thing will happen if that's how both reacts.