First time posting here, but been reading here for a while. So I am wondering how I should feel about this.
I have been poly my whole life, and my wife and I have done some swinging over the 10 years we have been married. I had 2 relationships some years ago that might have been potential poly relationships, but she reacted badly (and I didn't do a good job of reassuring her) so I let them go. There were other things going on besides her reaction. She has always said she was mono, but willing to participate in this in order to make me happy.
So a few weeks ago, she finds a guy (she has been looking for awhile, open to the idea of poly just never finding someone) she connects with. She goes out with him, and sleeps with him on the first date (Friday). They had been hanging out as friends before that (long story, just happened to be at the same place a lot, think coworkers) for a few weeks so it wasn't totally out of the blue, but still very quick. I spent the next day (Saturday) with very mixed emotions, and asked repeatedly throughout the day to give me some time to process my emotions. When I spoke to her that night, I told her the unexpected and sudden change had just unbalanced me but that I was OK and she should go ahead and continue to pursue her relationship.
So Monday, she tells me she is going to go out with some coworkers after work for free pie night at a local diner. Something didn't feel right, plus I knew that they were having a potluck at work that night so why would they want to go out to eat afterward? That night I was responding to an alarm call in that area at about the time she gets off work, and drove over to the diner. She is there, but it is before she usually gets off (and before she told me she was getting off that night) and she is there with her new guy. I don't go in, not wanting to make a scene, but watch for awhile then head home. About 4 hours later she comes home, and makes a big deal of being very loving and attentive with me. She sits next to me, rubs my leg, looks deep in my eyes with a sweet smile and proceeds to lie to me. She gives me a huge, detailed story about her evening with her coworkers, why it went so long, what everybody said, etc., all while staring me straight in the eyes and being physically affectionate. At one point I looked at her phone, and saw that long before heading to work she was planning to get together with him, and had then asked me about getting together with her coworkers as a cover.
I was stunned at first that she would lie so blatantly, and let her continue for quite a while and finish her whole story before telling her I knew she was lying because I had gone by after an alarm call and it was only her and him. She tried altering her story a bit, tried changing little details (coworkers were there for a bit then left, some had been there awhile, her guy hadn't been there until later) then tried to claim she had never told me she was going there with coworkers/had gone with coworkers. Fortunately (or unfortunately) I had actually been there and knew all of these new stories were also complete BS and told her so, and after a good hour of trying to finesse the situation she finally relented and admitted she lied.
I feel as if she has cheated on me. I have never had an issue with her having sex with other men, with or without me (and she has had several one night stands or even repeat dates). She told me that this was the first time she has tried lying to me, and it didn't go well, and shouldn't erase over a decade of good faith. I hear her, but it does. The lying, the sense of betrayal, and the way she was so affectionate and looking me in the eyes as she told me about an evening she didn't have in order to conceal spending time with this guy, it doesn't make any difference to me if sex was involved or not.
Unfortunately, my lack of trust in her over the last few weeks (looking at her chat history, checking to see if she is actually at work) has caused her to start concealing everything from me in some attempt to get back at me. She has stated she now does not trust me, because I am so suspicious and checking on her. I feel like saying "tough shit, I don't trust you for GOOD REASON and you are going to have to put up with a level of paranoia until you can start rebuilding that trust". She keeps saying "I apologized, why do you keep bringing it up." and "If you can't ever get over it, how do we go on?" I keep saying it's only been 3 weeks! It is like she either really believes it wasn't that big a deal (because they were only spending an evening together at a diner, not sleeping together), or she is trying to minimize it in her mind and mine.
Any advice from the experienced among you?