I had an oh shit moment on the scales last November. I knew things were bad but I hadn't realised how bad they actually were a had been dealing with dying parents. I was then in the position where I needed surgery but was too heavy to be referred.
Realised that every 'diet' I had ever been on had failed as I had regained the weight and I had to do something different this time and make changes I can stick with for the rest of my life. I thought about it and realised at the end of the day all the various things out there come down to one thing, creating a difference between your food intake and the energy you burn so counting calories seemed as good a thing to do as any.
I also got a Fitbit to see what I was burning. I got a Flex 2 which didn't have a heart rate monitor and is more accurate than the Charge 2 which does. I eat healthily about 80% of the time and can manipulate my weight loss to lose 1 or 2lbs a week average over I eat depending what I want to do.
Also realised of this is to work long term I have to be able to deal with things like birthdays, Christmas, social occasions and holidays. Christmas I decided I wanted to lose still as had a surgery target to meet so ate what I wanted Christmas Day and Boxing Day but kept track of it and exercised to make sure I evened it out then lost 1.5lbs the rest of the week. Last week on holiday I ate at maintenance. Looked liked I had gained 2lbs but think it was just water as am now quarter of a pound lighter than I was pre holiday.
I'm 5 stone down so far with a couple more to go so it is too early to say I have cracked this long term but I feel more confident than I have before that I a, going to get to where I should be and keep it there. I've introduced exercise, slowly at first then stepping it up to include running (Couch to 5k, can now run 5k whereas in April it took every thing I had to do 60 seconds) at which point I've had to up calories as I was feeling really tired.
Portion sizes have changed drastically and I use the ones given on Nutracheck as a guide. Made the decision that we will have another dog when the time sadly comes that ours goes as I know I will have to keep walking daily and without a dog would be likely to lose motivation which I can't let happen. I've realised it's hard work and that's the same for a lot of people who are a healthy weight, they work at it.
Good luck with it OP. Lots of supportive threads on here to help.