I don't think you should feel betrayed. Your current husband sounds like a good man that was trying in a small way to diffuse a stressful situation for all of you. His thought may have been that by giving her the flowers that the pressure put on the children and subsequently you during their visits would somehow be reduced.

Many of us have situations similar to yours, it is never easy to see how our children are so negatively affected. I know I try to put aside everything and only consider them whenever I deal with their mother.

I'm sorry that this may not help.....but again I don't think it was a betrayal at all.