I'm sorry this happened to you. I had a similar thing happen to me when I was younger. My roomate began dating a guy she knew I really liked. It hurts - bad.

But, you do have to move on. Get a new roomate; move if you have to. It's not worth living in the pain.

Start to act "as if" it doesn't bother you until it doesn't because you've gained new activities, behaviors and therefore, new colleagues to fill your time. Begin by taking care of yourself physically, mentally, emotionally and spiritually each and every day. You will see yourself feeling more whole once more.

I got through this pain. In fact, I haven't thought of it for years until I read your post. It brought a sad reminisent smile to my face. I understand completely. But, it was ages ago, and I've lived two lives since then. You will too, and more. I promise.

Peace!