Yes, you were right to tell your fiance.
So now is the time to take positive steps to recover from gambling addiction. It is a horrible addiction that takes our money and our time. We are so distracted when we gamble that we are a shadow of what we could be.
Definitely put as many barriers up as you can. As you said block bank cards, get gamban or similar on all your devices, self exclude from any local casinos/betting shops (you may not have visited them before, but if urges to gamble come, they almost certainly will, then you will not have access to them),
Get yourself on the support groups here. You will get great advice.
Try and look at why you gamble, when you gamble. Try and find triggers. You might need counselling here or keep posting and reading other peoples journals.
Finding other things to do is massive. Revisit old hobbies you have neglected, take up new interests.
There is much more but this can definitely help.
There is a much better life out there without gambling.