Just wrong and deserve the boot!!
That depends on you
Probably not, you should let the cheating spouse know that you know he's cheating though! If you want answers, you can contact the mistress to get the truth... although she may just direct you back to your spouse and tell you to talk to him (to avoid confrontation).
No it should not be considered cheating.
You should NOT being cheating on anyone. The above is correct. Stop now. Either with the "other" or the "spouse".
It means you should leave them.
cheating ANSWER: what about Adultery and Adulteress
Yes, some individuals can think their spouse is cheating when they are not. Some individuals have a jealous streak because they are not confident in themselves or perhaps have been hurt by someone else in the past that did cheat. Once an individual has been cheated on previously they are more inclined to be more suspicious of their new spouse cheating. This is where good communication skills is most important in a relationship and you should feel free to discuss how you feel with your spouse and then listen to what they have to say. There are male and female spouses who do cheat, but in most cases the signs are there or eventually the spouse cheating will give themselves away or be caught. We all risk a spouse cheating throughout our life spans, but thankfully a higher percentage do not cheat. Your relationship should be based on trust and if you do not feel you have it then work on it by communicating with your spouse or, if you are having difficulties with thinking your spouse is cheating there is nothing wrong with seeing a psychologist to get you over your difficult time.
Just because this person is a narcissist doesn't make then much different than anyone else cheating with your spouse and you should be more concerned about your spouse cheating. By all means sit down with the narcissists spouse and tell the whole story, but be sure you have absolute proof before doing so. Don't be surprised if the narcissist's spouse becomes angry and is denial, but, in time the spouse will become to believe it.
Cheating your spouse is not a good thing. It could land you into loneliness and other miserable feelings.
Your spouse teasing you or not talking is common. They are feeling left out as you are cheating on someone else.
No I think if they both want to work it out and the cheating spouse is remorseful then they should try to work it out.
When a spouse breaks that bond of trust it will take several months to possibly a year or more (of good behavior) for that cheating husband to earn the trust back from their spouse. The victim of a cheating spouse should never make it easy for the cheater to come back into their lives and continue on as if nothing has happened, but, they should not harp at the cheating spouse or the relationship would wither away. To err is human and sometimes either men or women make a mistake and cheat, but some never cheat again while others may find themselves cheating over and over again. This is why it is important for the victim of cheating to tell their spouse they will only take them back if they agree to go to marriage counseling where the marriage counselor can give them the tools to correct the weak areas in the marriage. If the cheating spouse refuses, then it is better to walk away from the marriage.