I feel for you. When I first wanted to stop – it made me realise how few real friends I had – because, as you say, after decades of gambling – which is a loner’s game, I had no-one close enough to open up to, never mind hand finances to.
It is possible to do this alone. It is far more difficult – so if you can find local support go for it. If there are no GA groups – there may be groups for all addictions which will help. Please investigate the counselling option. Again having this kind of support is invaluable – do the research, don’t just write it off as not possible without checking. If you can let us know which country you are in – you may find people on here that can give more local advice.
If you can’t find anything locally – then please check out the support groups on this site – there is a timetable where you can see times in GMT and adjust to your timezone. On Mondays and Thursdays (tonight) there are facilitated groups for new members. There are also “live meetings” on the internet from other organisations such as SMART and some facebook groups.
Basically get as much suppport as you can. Gambling is lonely and the way to stop is to befriend people and let them help you in the early stages. You can of course pay back when you are stronger by helping others. I wish you well.