Gambling has clear connection to divorce with studies showing that people with gambling problems have much higher divorce rate. Hiding your gambling from your partner is major issue as keeping secrets destroys trust that is essential for healthy relationship. If you get into financial trouble and have to tell your partner it can be shocking surprise that seriously damages your relationship. Using shared money for gambling without your partner knowledge is betrayal of trust. Ultimately financial problems and emotional stress and loss of trust caused by gambling can be too much for relationship to handle which is why it is so important to be open and honest with your spouse about your gambling habits.
That's when the problem begins, financial problems. If most of the money is being spent on gambling and the gambler cannot provide for the partner, especially if they have kids, then I believe divorce will be next.
Honestly, I don't want to end up like that, and I saw myself being left by my wife if I continue gambling. That is why I made a decision to just play moderately and use only the money that I know is acceptable even if all is gone. When you don't spend much, you don't really need to say anything as long as you are still providing what they need, including some of their luxuries.