Hi Craig, well done on looking for help.
It is good that you already know that you can stop gambling but need support. The good news is that there is a lot of that support around – here and other sites, places like Gamblers Anonymous, counselling and more.
Your fiancee can also hopefully help with some of the barriers you will read about on the other threads here. She can certainly help with accountability. Show her by your actions how serious you are about stopping, ask her to help with that accountability, get to those meetings, get a blocker for your devices that will stop you visiting gambling sites.
From what you have said about previous addiction issues I would add that this time don’t “just” stop gambling. Make sure that you find some healthy options to fill your time, a variety of options – that way you are less likely to switch from one problem to another.
Keep posting and let us know the positive steps that you are taking.