Caught In A Moment Of Weakness

I recently got separated from my husband of ten years. We tried counseling but it was clear we both needed some time to figure out if the marriage was salvageable or not. It's been a rough few months emotionally and I've been struggling with so much stress, anxiety, and loneliness. My grad program is also incredibly demanding and has left me feeling overwhelmed on top of everything else. One day last week, while on campus late at night working in the library archives, I ran into an old acquaintance from my undergrad days - a guy who had always been attractive to me but I never pursued back then because he was dating someone. He's now single and still very handsome, with a kind of charisma that pulls you in effortlessly. We started chatting over some research help I needed. We caught up on life briefly before going our separate ways. But later that evening, feeling lonely and restless, I sent him an email just to connect again - nothing more than small talk. He replied right away, saying he was feeling the same way after a breakup himself. I felt bad about my situation but also vulnerable and wanted human connection badly. We texted back and forth late into the night. By this point it was obvious where our conversation was heading as we both started opening up more personally. I couldn't shake these intense feelings for him even though I know rationally it's not a healthy thing right now. Eventually, after hours of texting, I found myself agreeing to meet with him at a coffee shop nearby early the next morning. We talked some more, mostly just reminiscing and acknowledging how we both felt - but also being careful about pushing any boundaries given our situations. Still, it was impossible not to feel sparks between us. He's so much more now than what I remembered back in college. Late that afternoon, I let him take me out for drinks at a bar nearby campus as my grad work had wrapped up early and I didn't have anything else planned. By then, we'd both admitted it was clear there were strong feelings still lingering despite our circumstances. The night got heated between us quickly - I couldn't resist anymore after so much built-up tension and desire. Things progressed and soon we found ourselves alone in his place where everything came to a head that night... I've never felt such a rush of intense emotions, but also guilt and shame for betraying my commitment to my husband. It was consensual all along, but it feels like the worst kind of affair even though I know he's no longer my husband. I'm just trying to process everything right now - wondering how could this happen when I have so much going on already in my life that needs sorting out. Writing this down helps me make sense of what happened without any judgement from others, which is why I never posted confessions before.