I'm sorry to say that if this started 18 yrs ago and she's beein carrying on with this guy for that long which is most likely, any details is moot. She's likely not going to quit and she is the type that thinks it's ok to have two lives. after 18 yrs do you really think that kind of a pattern will change in any kind of reasonable time frame? She needs more than just talk but actually the realization that it's over or you're gone. This is one situation where I really recommend walking away at the very least for a physical separation.

I hate to bear bad news but somehow I dont' think my info can top how badly I'm sure this has traumatized you already. I'm sorry you're going through this.