The answer to the question is, it depends on 1 thing.
Is there any possible way your partner will find out?
If the answer is “yes” then save your partner from the excruciating humiliation that they will suffer if they do find out. Even if there is a small risk, it’s not worth taking it after your disgusting behaviour, the least you can do is to save them the embarrassment of talking about it behind their back.
However if by chance you’re indiscretions happened to happen on a desert island where there was no witnesses with a stranger who will never be back in your life, whom you have 0 mutual friends then do not admit to cheating. The best thing you can do is try to put your partner off you for example stop getting a shower, start kissing badly, don’t brush your teeth. Let your partner go off you. This is the decent thing to do after the way you have treated them.
Let them feel like it is them that has ended the relationship. Whatever you decide to do, the relationship must end. Let them be the one to end it. You at least owe them that.