I won't lie and say that it's easy, but it can be done.
I gave up actively ttc after about 2.5 years, that is to say I told myself it was never going to happen (I never did charting etc although knew where I was in cycle). But deep down I always told myself that giving up meant I might fall pregnant, as that's essentially what people say (give up and you'll get pregnant).
I always considered myself to still be ttc, but it was always in the knowledge that we couldn't get pregnant.
A few months ago we discussed the possibility of IVF, fueled in part by the fact sil is having ivf atm, and we did discuss whether we should pursue it, or whether not doing so would mean we'd regret it for ever, however the indecision over it led us to realize that it wasn't for us, and so we have now definitively made our peace with not having any more children.
I'm not on the pill, I've been not using contraception long enough to know that it can't happen, so am positive I can't have any more children.
For me it was all about concentrating on the positives rather than the negatives, and also trying to look at the impact another child would have on us. So for eg we went to the states last year, something which wouldn't have been possible with a baby, I look at the age gap now, I look at my healthy happy ds, and think that it's better to concentrate on the things I have rather than the things I don't/can't have.
Maybe just stop charting and don't use any contraception but stop thinking about it all, spend time with your existing dc (if you have any). if you don't have children, perhaps think about whether assistive conception is a path you wish to explore, and if not, then live your life for the things you enjoy now, and the rest will follow.
And don't kid yourself that giving up will mean you'll fall pregnant, because it's that belief that means that in reality you're not giving up at all.
Good luck.