Caught My Husband Cheating - The Details Are Intense

I've been married for three years now. We were college sweethearts and seemed to have everything going for us - good jobs, a comfortable home in the suburbs, and what appeared to be a perfect marriage from the outside looking in. Or so I thought. A few weeks ago, my spouse came back late one night after saying he had dinner plans with his buddies. But there was something off about him. He seemed nervous and overly affectionate at once, which only made me more suspicious. So the next day, I decided to dig into our phone records. And that's when I found out he'd been texting a girl named Sarah on the side for months. At first, I tried to give my husband another chance. We talked it out - him claiming it was just late night drinks and innocent chats, me trying desperately not to believe his lies. But then two nights ago, I got home early from work and found them in our bed together. The scene was unmistakable: Sarah's clothes scattered on the floor, my husband still naked under the covers, looking panicked. I don't know what made me do it, but as they scrambled to get dressed, I walked over and watched him finish with her right there, while I stood in the doorway observing. The sound of skin against skin, his thrusting hips pushing into her body - I saw everything clearly and felt nothing emotionally at all. Just a clinical observer witnessing sexual acts. Afterward, my husband was begging me to forgive him. But seeing him like that with another woman, being so intimate with someone else while I stood by watching...it broke something inside of me. I ended up walking out on him that night and haven't slept in the house since. The betrayal is too much right now. I don't know what my next step will be yet. Maybe I'll give us a chance to work things out, or maybe this was the end all along. Either way, it's not something I want to take to therapy - just needed to get these details off my chest for myself.