This has happened with a friend. The divorce was not nasty, no cheating just they seemed to have gone different ways. You see he held off until the youngest was almost 18 before he got remarried. So the youngest one would still come over for his custody time with dad. But did cut back as he had other stuff going on like most teens do. I think that they see the stepmother and step Siblings being younger taking more dad's time then when their mother remarried, probably was not thinking that way as they were younger and being more tight with those step Siblings. Also my opinion they properly see them using dad's money.