They Start Demanding A Small Break
If they ask to have a small break, then accept the fact that they are cheating on you. At first, they tell you that they want to have a break for a while, then during that period you wait for them to come back, they go ahead and have multiple affairs, and you still wait.
After a couple of months, there is no indication that they will come back. During this period you might have sex from time to time but it is highly unlikely. The best course of action is to not beg them to come back and just accept things as they are and move on with your life.
If you act indifferently then they might come back and try to have break-up sex with you. Whatever happens, just keep cool and try to make them jealous by going out with other people.