A little secret here. I am also married besides my female co-worker friends my other friends are the wives of my friends. But I noticed that I try to keep the friendship because of their wives than the husbands. It is not that I am sexually desiring their wives (or am I?).
My perception of what happened with your co-workers is that they always had feelings for you and you didn't noticed. Maybe they were too subtle when you were married, but the interest for you was always there.

I don't believe that's totally true. Everyone is attractive in their own way; and even though men are attracted to what they see while women are attracted to what they hear, sex is imprinted in men since puberty. I have fat friends and I can tell you that I had sexual feelings for them too. So I don't thing that being fat is a factor here. Do you want to be my friend :-P ?