I did, but it was TT, and he only got the full truth a few months ago, 30 years after the A. I came clean about the sex right away. At the time, it was the height of the AIDS crisis, before there were any treatments, and diagnosis was a death sentence. I had had unprotected sex with the OM, who claimed he had never slept with anyone else; surprise, surprise, I discovered shortly afterwards that that was a total lie. 
So I knew I had to tell my BBF that I had been exposed to the possibility of HIV, even if I could have lied to him about the sex otherwise. (I keep typing "which I don't think I could have" and then deleting it, because I told him some other enormous lies, so as much as I want to believe that, I guess I can't say for sure.) We were each other's first and only, so this was obviously devastating news. What I *didn't* tell him was the full extent of the sex or the emotional involvement of the A. I admitted that we'd committed other sexual acts, but I minimized their frequency and intensity. I admitted that I told the OM I loved him, but I made it sound like it was something I said back to be polite, rather than multiple affirmative declarations. And I told him the sex was only one time, and practically a misunderstanding -- a brief encounter that made me feel violated afterwards. In reality, it was something planned that I participated in fully; one night, but multiple encounters and positions, and a romantic declaration of consent.
Why did I TT? I'm afraid it was the usual reasons. I was trying to evade responsibility for my actions and avoid/ control their outcome. During the A, I had managed to shut out any thoughts of consequences. My BBF and I were in a long distance relationship (different colleges), and I had gotten permission to date the OM casually. With each new physical activity, I convinced myself that what I was doing might still fall under the terms of our agreement. By the time that I was clearly over the line, I was so adept at lying to myself that I just blocked out the inevitable fallout. OM was graduating and moving across the country, so we had agreed at the outset that our relationship had a defined end date. As the end approached, he wanted to stay involved. He never point blank asked me to break up with BBF, but he amped up the romantic declarations and manipulations. I felt guilty that I was hurting him by ending it (I know how ludicrous that sounds now),so I had this crazy idea that I could ease his pain at the end of the PA by staying friends with him. At the time, I didn't even understand what an EA was, or that I was in one just by staying in contact, regardless of whatever new boundaries I thought I was imposing.
In the time between ending the PA and telling my BBF about it (which was a few weeks; we were still hundreds of miles apart, and I wanted to tell him in person), the denial started to melt away and I could no longer avoid facing what I had done. Honestly, I thought my BBF would break up with me as soon as I told him about the sex. I had always thought he had the upper hand in our relationship, and that he was fully capable of walking away. He had broken up with me when I graduated from HS, saying that long distance relationships rarely worked, and he was the one who, after we got back together, said we should be able to see other people. I figured that admitting I'd slept with OM would be both the beginning and the end of the conversation, and after some harsh parting words, I'd be on the train home the next morning. So while my memory on this is hazy, I think I decided to tell him that I had slept with OM once (selling myself on the idea that multiple times in one night was technically once) and then brace for the breakup. I was prepared for BBF to be furious. I wasn't prepared for his devastation. It destroyed him. He was sobbing uncontrollably, and despite the risk of STDs, clung to me for HB sex. When I realized that he wasn't instantly firing me, I went into total damage control mode. I couldn't face telling him more things that would break him, and I rationalized that he already knew the worst thing, that I had slept with OM. So these two completely contradictory thought processes kicked in: 1) I've told him the most important thing he needs to know, so I've been honest with him; and 2) there's no way I'll ever be able to be completely honest with him, or he'll leave. Everything I told him from that point on was designed to give him a version of the truth that I thought he could live with, rather than the genuine honesty he deserved. After several years, I even sold myself on the lies, and believed I had been truthful.. except for a few minor details.
So how and why did I finally come clean? Unknown to me, my BH never recovered from the trauma of the six months between DDay and my final agreement to go NC with OM. He was aware that OM had not wanted to end it and was looking for an opening to get back together, even though he was thousands of miles away. I was getting ego kibbles from having two men vying for me, both of them long distance, and justified that I had a right to be "just friends" with OM because I no longer did anything physical with him or said anything romantic. I was absolutely not a candidate for R. I didn't break off contact with OM until BBF and I decided that we either needed to break up or commit fully by getting engaged. NC was a hard condition from BBF, so I agreed, but we stopped processing the A and rugswept the fallout. The damage had already been done, and the trauma followed BH through our entire marriage.
As midlife hit, BH became depressed and decided that he needed to finally find a way to get past the mind movies and insecurity that the A had caused. I had no idea that this had been going on; as a typical rugsweeping wayward, I thought that we had put it all in the past. He started to ask me questions about specifics of the A. He thought he was just refining small details if what he already knew. I panicked. I hadn't thought about many of the things he had asked me in years, and I had genuinely forgotten a lot of the details, but subconsciously (and increasingly consciously), I knew the key pressure points. Those were things I had long ago decided to take to my grave, and there was literally no way he could ever find them out except from me. This was when, thank God, I found SI. I read about how there's no such thing as a good lie, and the critical need for honesty in order to heal. I wish I could say I sat down that night and told him the full truth, but it took about a month of TT for me to drag it out. It was almost like I had to fight and outsmart my own brain, which had spent 30 years double-bolting those doors and throwing away the keys. There are really important things I truly, truly can't remember, things that you'd think would be so significant that I couldn't possibly forget. I can't remember most of the night of sex, just flashes. I can't remember anything about what I said when I called OM and declared NC. I can't remember how many times I engaged in specific sex acts. But there's a lot I could and did finally tell BH -- the flashes I remember, the words, things OM said and that I said, what I was feeling when we were together, the real story behind the lies and minimizations. When I got to the truth behind the last and worst lie, I was just as scared that he would leave me as I was that night in 1989. He had even better reasons to leave me than he did then -- I tricked him into marrying me, letting him think he had the whole story of my A. Letting go of that outcome was the step I could never have taken without SI.
I am so grateful that my BH wants to pursue R with me, and so remorseful about the TT. I can't believe what I put him through.
[This message edited by BraveSirRobin at 10:12 PM, February 4th (Monday)]
