My First Time Since Separation

I was so ashamed when I finally gave into temptation last night. After months of being single and trying to rebuild my life, I ended up at a friend's party where I met this guy named Jack. We talked for hours, then went back to his place together. It felt wrong, like betraying everything I've worked towards, but the physical craving was overwhelming. In my room, we were careful but didn't talk much, just let our hands and bodies take over. Afterwards, I felt dirty and guilty. Am I a terrible person for wanting this?