When I Crossed the Line with My Sister's Ex-Husband

I was going through a rough patch after my recent divorce. The stress and loneliness were overwhelming, and every night felt like an eternity. To make things worse, my sister got divorced around the same time, and her ex-husband, who we’ll call Alex, started reaching out to me online. I knew it wasn’t right to get close to him, but after a few months of talking, he invited me over for drinks one night. At first, we were just friends, or so I told myself. We bonded over our shared experiences and the pain of ending marriages. He’s in his late 30s now, and there was an undeniable chemistry between us from the start. It started with long conversations about everything under the sun, kids, work, hobbies, you name it. Then one night, after a particularly exhausting day at work, I showed up for drinks and ended up staying longer than planned. We talked late into the night, and as we sat together, his hand brushed against mine accidentally. That simple touch sent shivers down my spine. It felt like an unspoken agreement to move forward. A week later, he texted me that his marriage had officially dissolved, which made me feel even more conflicted about our growing closeness. Despite everything, we started seeing each other behind the scenes, drinks became dinner dates and casual hangouts turned into late-night talks over coffee. I knew this was crossing a line, but Alex's company filled a void that no one else could. One evening, after too many glasses of wine, our touches turned more intimate. We kissed, held each other, and eventually went beyond kissing. It felt liberating yet terrifying all at once. The next morning, I woke up with regret but also a strange sense of relief. Was this just an escape from reality? Now that the dust has settled, I know what we did was wrong by every standard. Still, I find myself questioning if it’s entirely my fault for seeking solace in something forbidden. My ex-wife and Alex's ex-wife are both moving on with their lives, while I’m stuck here, feeling lost. I need to talk this through, am I just the asshole here, or is there some understanding of why this happened? Would it be fair to seek closure from him now that he’s officially single too?