Bella, welcome to the forum. One thing you will see is if you address one sufferer you will have more than one respond. I have seen Anthony stress many symptoms or indiscretions PTSD sufferers are likely to do over time and I know my own experience. On this one topic I think it may seem more prevalent recently as so many people are posting about spouses or girlfriends/boyfriends wanting a "break" from a relationship. There really is no such thing IMO. It is I want to do what I want while you can't, or it will give me something to hold against you later.
Yes, many use this as a reason to go out and "cheat" but if you are not in a relationship is it really cheating? Again there is really no such thing as a "break". You are either there or not. These breaks are child's and head games no carer should tolerate IMO again and tell the suffer so. Draw a line.
Being cut off emotionally is not the same time as a break up or one of the infamous "breaks". Just because there is a shut down on one side does not mean they are out or possibly cheating.
On the other hand cheating can be part of common risk taking behavior. Just like you get lost in a bottle or other high. It is just something new and different and being that it is an escape from reality. When you are done you throw it out just like an empty bottle and no longer have use for it. You don't care if you are risking your life as you normally wish for death before healing and sometimes during it. You are selfish and cannot escape your personal hell. You don't feel like you have time for things as small as another's feelings that love you. You don't come back around to understand those things are not small until you begin to heal. Then you spend time trying to fix that mess you made. It is a very twisty warped path, but one that can be over come. This is up there with suicidal behavior, drunkenness, drug use, risk taking...
Of course Anthony's take may be different. This is just mine.