Well I'm glad I could help texasstep. I am also a step mom (again) so I completely understand. Believe me. More than I want to! ha
I was a step mom prior to my divorce as well and these issues are a huge reason why we divorced.
One thing I've realized is that these fathers often times act out of guilt and we just have to let them do what they're going to do anyway. The more you practice letting it go, the better you're going to get at it.
The Serenity Prayer or thoughts along those lines helps
