Flawed, I would mention one additional item for your consideration as you work with your BH. When a BH discovers that his WW (I use those terms realizing that the two of you weren't technically married at the time, but you were living together and had moved to a new city together contemplating marriage) has been sneaking and lying for the specific purpose of having sex with another man, it is very common for the BH to suffer feelings of sexual humilation and emasculation.
"It was just sex" is ironically one of the worst things a WW can say to her BH in this circumstance. I'm pointing this out because it has been my observation that many women don't understand this. It's not intuitive to women.
What a man hears when his WW, who repeatedly returned to another man for sex, while lying to her BH and concealing it, says, "It was just sex":
(a) I'm trying to minimize the magnitude of my betrayal (which men find patronizing and infuriating); and
(b) The dick he was giving was so good, and so much better than the dick you were giving, that it was worth it to me to lie to you, deceive you, risk our entire relationship, and put you at unwitting risk of catching an STD that could affect your entire life (I'm assuming you didn't use condoms in the A -- condoms are rarely used in A sex in my observation). I didn't need anything more from him to justify imposing that level of cost on you. The "just sex" was enough for me, compared to the degree to which I cared about you as a sexual man.
There are many incredibly long threads around this topic in the General forum. For a man, the calculus is something like this: if she was willing to lie to me and sneak around, and she did it for the express and sole purpose of sex with another man, then she must have preferred the other man sexually, and stayed with the BH only because of his characteristics as a reliable provider and steady parent figure.
There is an emotional corollary to this, which is also hurtful to the BH. Marriage is supposed to involve complete intimate knowledge of one another. When a WW secretly has a sexual relationship with another man -- in most cases, the other man knows that the WW is married/committed and often during pillow talk he learns a great deal about the intimate details of the marriage -- she creates a secret, private sphere of intimacy in her life that she carves out of the marriage. It becomes a hole in the "intimacy continuum" of the marriage, a piece of the WW's intimate life that she has allowed another man to own, in lieu of her BH.
These reasons underscore one of the basic messages from several of the posters on this thread: the most important thing you can do is to be 100% transparently, nakedly honest with your BH about every detail of this A that he asks you about. This includes details that he will likely find painful at a personal level. Do not attempt to minimize! The damage is done by now. You are trying to repair it. The starting point is by restoring the intimacy continuum, which you do by showing him that you respect him enough as a man to be frankly honest with him about everything, as if he was present the whole time watching what you were doing, so that he has the complete picture upon which he can then base his own decisions.
As to the "it was just sex" point above, there are many WW's on SI who have posted at length explaining that, from a woman's perspective, and A involving "just sex" does not mean any of the things I describe. I respect their sincerity and understand, at an intellectual level, what they are saying. At the same time, I know what men feel about this at a visceral level, or, more accurately, a foot or so south of the viscera.
It makes the BH feel negated as a sexual man, as if he was the sexual Plan B. Many BH's, faced with that circumstance, experience difficulty functioning sexually. They question their abilities as a sexual man. To a man's view, the only reason a committed woman would sneak for sex is because the AP gave her better sex.
I'm not saying that your BH feels this. I'm just telling you that this is very common among betrayed men, and therefore you ought to be mindful that it may be something he feels. If he does, this is something that is difficult to overcome.
Also, it makes a difference where the discovery is years after the actual A. If the sex in your marriage was very good in the years prior to disclosure, this will buffer the impact of the disclosure. If it was tepid, and you step up your sex game now, in the wake of disclosure, he may see it as patronizing and insincere, which could have the effect of exacerbating the issue. But if you don't, he could see this as confirmation that you don't enjoy sex with him. This area is fraught with peril from your perspective. You must tread the knife's edge.
In my observation, a man's sexual ego is way more fragile than many women realize. And in particular, a woman who is generally considered beautiful often has no clue about how profoundly this can affect a man.
Editing later to echo Zug's post below:
Please also resist using the word "mistake" when discussing either the A or the decision to conceal it. This was not a "mistake". A mistake is something like adding a tablespoon of baking soda when you meant to add a teaspoon. To engage in infidelity -- especially repeated infidelity that is intentionally concealed from a spouse for an extended period -- the wayward spouse must make many individual decisions, probably hundreds of decisions in your case. Flirt with another man in a way that is outside the scope of your relationship. Flirt more. Choose to be in physical proximity. Alone. Choose to allow physical contact. Choose to kiss. Choose to allow him to enter you. Etc. Choose to lie to your husband about it. Choose to lie again.
Consider the first time you decided to have sex with the AP. Why did you make that decision? Then think of your decision train for the period of, say, 24 hours surrounding that event. You decided to leave the home without your BH. I reckon when you made that decision, you had at least a hunch you would have sex with another man. What did you decide to tell your BH at that point, and why? What sex acts did you decided to do with the AP, and why? When did you decide to return home. Why that time? What did you do when you returned home, and why? Was your BH there? Did you immediately kiss him? Shower? Other? The point of understanding whys is first understanding the myriad decisions that went into taking the actions that constituted the A, and figuring why you made each of those discreet decisions, in each of those particular moments.
Each of us is the sum of his choices. I've been married for 23 years. I've had moments of temptation, like many married people. Often these have occurred after too much to drink, while away on the road for work, in circumstances that might make it easy to push my wife out of my mind. Some how, when I've found myself there, at the point of making the next decision that might start me down the slippery slope, I've been conscious of my promise to my wife and I've made the other decision, the decision to return to my hotel room alone.
The path to healing is to own each of the discreet decisions you made, without minimizing. Figure out what led you to make those choices and fix that so you are safe and won't make them again (it's possible you have already done this). And then figure out how to make your BH know your desire and love for him is true.
[This message edited by Butforthegrace at 8:29 AM, November 19th (Monday)]