What I get from reading this thread is that although people have different perspectives, all perfectly reasonable, there is a trend to think that whatever perspective one agrees, they think it should apply regardless of the individual involved and this is why I personally think it often goes very wrong.
There is no one way is the right way for all and I think that's what I've really learnt with my children.
The point of blending a family is that your little unit becomes a bigger unit.
This is exactly what my ex and his partner believed in. In many ways, it was a good approach, treating all the children the same being the right thing to do. It worked well with my DD who blended quite well in that family and found her place. It was a disaster for my DS. Why? Because my DD is family oriented, extroverted, the children involved were all girls, so it was easier for her to identify with them and she is just an easy unemotional child who rarely gets upset by anything.
My DS however is introverted, doesn't feel comfortable in groups, feels much happier in one to one situation, needs his own space, doesn't open up about his feelings unless he feels totally secure, and won't demand anything, but will just back off from situations he doesn't feel comfortable. What he needed wasn't a blended family, but a father that was going to give him some male one to one time.
SMs have different needs, fathers have different needs, children have different needs. Children comes first means that their individual needs based on their own individual personalities are taken into consideration.
I do agree with you Banana that everyone's needs should be taken into consideration, but when the needs of one clashes with the needs of the other, it becomes very hard for the person who's expected to answer to those needs to do so for all involved. I am in that situation and it is very hard. At the moment, I am managing it although at a cost to my stress levels.
Kids come first though means that if one day, I thought that my kids well-being was affected to a point that there was nothing I could do to make them better than to leave my OH, then yes, I would pick my child over my OH because my child is my responsibility, my OH isn't.