It does hurt. No way around that. I remember the first time (yea, you heard that right) I asked my husband to choose--me or the beer. He looked me straight in the face and said BEER. I was devastated. Eighteen years of marriage and two children, and he would rather have the beer! And it still took me another year to kick him out.
There is a saying (I believe it's Buddhist) that goes something like "pain in life is mandatory, but suffering is optional." While the pain of losing the relationship is awful, it's nothing compared to a lifetime of suffering and staying.
I hope you will continue to post here as you work through the pain and find that a beautiful life awaits you on the other side.
L