I don’t know if this might help, but years ago I read that while your peeing, stop the flow a few times. It helps develop the ability to stop yourself cumming. It might be hog wash.
What I tend to do when I know am close to blowing my load is I stop, sometimes take it out if am inside her. But usually just stopping thrusting for a few seconds will help to delay it. Word of warning though, stopping it too many times can cause the erection to disappear.
Also try new positions, deep positions that mean you’re not thrusting, her on top sitting, doggy is a great one. Go deep inside her and grind against her bum cheeks. My wife orgasms every time when I do this and I last for ages.
The cross position is also a good one for controlling thrusts and try to go a bit slower, it will help you controll your orgasm as your going slow and will feel it starting.
Hope that helps