My marriage was similar to yours, in that I was married to a nice guy, yet I had multiple affairs. Most of my A's weren't full on PA's (only 1 was a full on PA), but that doesn't really matter. They were all wrong, either way. Anyway I just thought I would chime in, in case I can help you at all.
I think there may be some different dynamics at play in your marriage than there was in mine so I will state a disclaimer: I have just recently realized that I am a sex addict. I never understood this term at all when I was younger, so I never even fathomed that it could apply to me. But now I understand that sex addiction can look totally different in different people.
In my case, I was and still am addicted to sexual attention. I always thrived on getting the type of attention you get from a man who wants in your pants so bad you can both taste it. I know that sounds so awful, but what I have come to realize is that in my current relationship, I can get all the attention I need from ONE PARTNER. So my addiction doesn't have to be fueled by a variety of men (although in some sex addicts I assume that variety is part of their need), I can be very satisfied and happy with the attention of just my partner. When I was married, I never understood this about myself at all. All I knew was that my husband wasn't "doing it for me". So when someone else started paying me that type of attention that drives my addiction, I would follow in their direction and not even want to, but feeling unable to stop myself.
My ex-h is/was not a very passionate person. He was also not a very sexual person, although he loved sex and wanted more of it from me. For many years I struggled to understand myself and explain myself to my H. I did many things to try to get him to pay me the kind of attention that was getting me into trouble outside the marriage, but he couldn't seem to find that within himself. From the time we met, I was the one who pursued him, which I know undertand is a poor relationship dynamic (ie: the man should pursue the woman because if she pursues him, he will eventually lose interest in her, per Mars/Venus philosophy).
He wanted sex, but he didn't want to make a priority out of finding out what turned me on. He just wanted simple sex, not much in the way of passion, and he didn't really have great skills, either.
So we were stuck. He couldn't turn me on yet I had an insatiable need to be sexually admired and attended to. I wished and wanted for my sexual needs to be met by HIM. I did not want to go outside the marriage. I never wanted that. I felt like an A-hole and just stewed in guilt for 15 years.
Had I understood these dynamics at play, we could have possibly fixed this issue.
But first, he would have had to do like you are doing and begun reading and understanding (or trying to) what it takes to be passionate, what happens when its missing, and I needed him to study ME and find out what makes ME tick. I think he was always intimidated by my sexuality (there's a lot of it in me, LOL!) and so he just didn't even try. But he would have had to try if we were to make it, and in retrospect, I know now that we might have.
So I don't mean to alarm you or make you afraid that you will end up D'd like I am. I just want you to hear from another woman who is maybe similar to your wife (though I'm not sure about the sex addiction in her, I haven't read enough of your sitch to understand that part yet). I want to say that I never ever wished to hurt my H, even though obviously the things I chose to do couldn't do anything but hurt him. It is a very strange dilemma when you are in the middle of it.
The one thing that is different in our sitches that is maybe not a good thing, is that she doesn't want to talk about it.
In my case, and its still the case now, I will ALWAYS want to talk about relationship issues, ALWAYS. Even in my current relationship and every thing is good right now, well then when we talk about relationship issues we talk about how good it is and what we are doing right! So good or bad, I always want to talk about it. The fact that she shuts down and won't talk is very unhelpful, and if she is to reveal herself to you and help you understand what is within her that lights her fire, how can that happen with no talking?
Can you tell us anything you know about her A's as far as, is there any pattern you can see? What was she getting out of it? Do you know anything about what actually "happened" once they entered the physical part of the A? I'm sorry that these questions might really hurt you to think about, so just skip them if its too painful. All I am really trying to do is get an idea of what she keeps chasing outside the marriage and help you to develop whatever "that" is, so maybe she will chase you one day.
