Stuart……it will definitely take time, but it is hell going through it. My dreams were shattered too after a 19 year relationship, 16 years of which we were married. It was due to another woman but he found many insulting ways to blame me for the demise of our marriage. It didn’t matter that I still loved him deeply and that I was shocked he could throw away all our years together. I feel your pain because I had plenty of it myself, so much so that I could barely function for a long time.
Getting counseling for yourself is very important because this is a devastating life event for you. I wouldn’t have survived without it. Take good care of yourself and take life one day at a time. I suggest you also find another place to work. Seeing her every day in these circumstances is not healthy for you in many ways. You need to distance yourself, or you will forever be caught up in an emotional roller coaster that will only keep you very stressed out.
Hang in there. It will get better.