my wife use to kiss, but now I she is starting to avoid kissing during intercourse, I feel she is disgusted, further I think she is even sleeping with me just for the sake of being a family.

I suspected that it may be a mouth smell, but nothing has changed further I even started to brush my teeth more frequently , and use mouth wash before having sex. I feel she has lost some kind of interest in sex, although she climax intensively and she enjoys the moment physically but instantly rise up and goes to the toilet as though nothing has happened, although she use to hug me or give me a kiss after that, she even use to climax twice during sex. I feel that she does not love me anymore, but she is tolerating the sex relation just for the sake of the family. we have been married for 14 years. is this a sign that she is cheating on me ?