Infidelity/the LRT (while the affair is going on, or if your partner will not stop seeing the other person and you want to work on saving the marriage)
p. 216
"You also have some investigative work to do. No, I don't mean snooping around to find out what is really going on. Since you can't approach your spouse with any information you discover, you are only hurting yourself by snooping. You need to figure out what is so darn appealing about this OP. Do they have a great sex life whereas yours has been paltry? Does s/he flatter your spouse a great deal, building his/her ego? Is s/he spontaneous, willing to do things at the spur of the moment, when you like to have things planned months in advance? Is s/he a good listener, always interested in what your spouse has to say?
You need to find out what need your spouse is fulfilling by spending time with this person so that you can do a better job fulfilling that need yourself. You need to make some changes. Don't tell your spouse that you are going to change or that things will be different, just start acting differently."