The Office Romance That Turned Ugly

So here's the deal: I'm in my mid-thirties and have been engaged to Sarah for two years. She's an amazing woman, but work has been a bit of a pressure cooker lately. My team and I are on this big project deadline that's had us pulling all-nighters. The whole office is feeling it, especially my coworker Mike, he's a married guy in his late twenties who's always seemed like the type to keep things strictly professional. But something shifted last week. We were working late together and I think we both just needed a moment of escape from reality. There was this weird tension in the air that felt almost palpable, and before either of us could blink, it happened: we ended up kissing at his desk when everyone had left for the day. It's not like we fell into bed together or anything overly dramatic; we just kissed a few times over the next week when nobody was around. It wasn't about lust so much as this strange mix of exhaustion and release from daily stress, but it was still very wrong, despite how consensual it felt in that moment. Sarah and I are planning to get married next year, and honestly, we've both had our struggles since we started dating long-distance back when she worked out-of-state. She's never been this demanding about our sex life before, but lately... well, I don't know if it's just me feeling a bit neglected or what. Anyway, the other night after yet another late meeting with Mike (who's also my boss), he texted to say he had something important to tell me. When we met up in his office, instead of an apology for our brief affair, he dropped this bombshell: 'I'm not married.' It turns out he was having issues with his wife and decided to leave her while they were still under a mutual non-disclosure agreement at work. So now I find myself torn. Part of me feels betrayed by Mike, who's clearly been hiding something big from everyone, even me, the guy he confided in when he felt like breaking things off with his wife. But another part wonders if this sudden shift is why we started hooking up to begin with. In all honesty, I'm writing this as much for my own headspace as anything else. There's no one at home who'll understand, I don't know how to break it down without sounding like the asshole here. But it happened and I need to process it somehow.