she's scared she might not have a chance with your husband again.
ask him
this is an easy question: see if he goes places alot and be on the phone too much.
There really isn't a way to know if your husband is not cheating any more. You will need to trust that when he tells you he is not cheating that he is not. Of course, you could hire a private investigator to follow him 24/7.
cheating is doing anything you wouldnt want your wife/husband or girlfriend/boyfriend to know about
I would say watch out, but I dont know why someone would knowingly marry a sociopath in the first place.
You are in total control of yourself and you don't need permission or even to wonder about talking to your husband about his cheating. Let him know what you know and tell him if he continues to cheat you are filing for a divorce. Take control!
Getting offensive towards a cheating husband does not resolve the problem. If it is the wife that has caught him cheating then she can give him two choices .. seek marriage counseling and stop seeing whomever he is seeing or she will file for divorce. If it's a relative or a friend then they should talk to the husband and tell him that he has a week to come clean with his wife or you will say something, but it would be wise to also let him know others know about his cheating just in case he may seek revenge of his own to keep that person quiet.
Unless you find him in bed with another person, you won't know for sure.
If you have absolute proof that your husband is cheating with this other woman then you should deal with your own problems with your husband first and yes, the other woman's husband should know. This is not an uncommon problem and most people (whether a husband cheats with another man's wife or a wife cheats with one of her friend's husbands) is very common and the victim of the cheating generally does tell the husband or wife that their spouse is cheating with their spouse.
Because you're having sexual intercourse with someone else.
it means you are cheating yourself. and you know that thing v ery well. don't cheat yourself its not good.