Recently on Glee, the mother of Finn (quarterback) and father of Kurt (gay guy with crush on Finn) were brought together by Kurt, who had his own happiness in mind, entertaining visions of sharing a bedroom with his crush. The widow and widower hit it off, but not everyone was pleased. When Kurt proposed a characteristically hyperbolic toast to "the new family" at a diner one evening, comparing it to the union of the Bouviers and the Kennedys, Finn took issue not with the grandiose analogy, but a more basic claim. "We're NOT a family," he intoned with great disgust and conviction from his corner of the booth.

Granted, these are TV characters we're talking about, and in the story line they are merely dating. But the truth is that stepfamilies are the new norm, outnumbering first families in the U.S. as of 2010 or 2011 according to numerous demographers. And in real life, too, those who begin getting serious with a potential partner after divorce or the death of a spouse are frequently in for a whole lot of blowback from their kids of any age. And it generally doesn't much matter how long they wait to do so. Whether these kids are four or 44, experts told me as I researched and wrote my book Stepmonster, a child or adult child's first response to a parent repartnering is often, "Why?!" followed shortly by "Don't!" Loyalty binds can be tremendously powerful regardless of one's age, and seeing mom or dad move on may well feel like a horrible betrayal--not only of one's other parent, but of oneself. "We used to do everything together," one woman in her twenties lamented to me of her father's remarriage. "And then there was this realignment. I like dad's wife, I liked her when she was his girlfriend too. But I don't like the change in my access to him, in my central position in his life. I used to be first. It was all about me. Now it's not and it's hard. I know it's childish but I can't help it! I'm working on it."

She's not alone. British psychotherapist Sarah Corrie, one of the few to work with and write about the emotional reality and psychological challenges of adult stepchildren, found that counter-intuitively, the older the child, the more difficult they were likely to find it to assimilate a stepparent. She suggests this may be because the young adult or adult has, over the years, worked out a very intimate peer-like or even spouse-like relationship with his or her parent. Add to this the fact that, developmentally, a young adult or adult has less need for an additional parent-like figure, or even what Boulder, Colorado psychotherapist Mary Kelly- Williams, who specializes in treating stepfamilies, calls, "a dependable ally," and it's clear that it can be especially tricky for an adult to get a stepparent, and for a stepparent to get an adult stepchild.

Role ambiguity--who is this person to me? what are we to each other?--dogs the adult child/stepparent relationship in particular. And this can come as a big shock and disappointment to the stepparent who had his or her heart set on a "blended" family, an expectation so widespread and so unrealistic that the National Stepfamily Resource Center has been asking therapists and the media to cease using the term for several years now. The reason: stepfamilies are different from first families in so many ways (start with the reality of a divorced or deceased parent in the picture; end with lower measures of closeness and cohesion than in first families even in stepfamilies that work well and feel "happy") that expecting them to "blend" and come to resemble a first family sets everyone up for failure.

Even when the children are very young and open to forming primary attachments, stepfamily experts agree, the blended family model is problematic. "When you say you're a blended family, what are you saying about that child's other parent? You're putting that child in a bind," explains Francesca Adler-Baeder of the National Stepfamily Resource Center. The model works no better for parent and stepparent, who set themselves up for marital stress and rejection by the kid/s. A better alternative to the blended model is embracing reality: the child already has two parents, and even if one of them is dead or negligent, acknowledging that the stepparent won't try to replace him or her will set everyone at ease and increase the chances of stepfamily success.

But back to fantasyland for a moment. In spite of Finn's loyalty bind masked as grumpiness, he eventually cedes some ground, inviting his stepfather-figure to join him in watching a game on TV, even moving the urn of his father's ashes aside so his mother's beau can sit in Dad's Recliner, a sacrosanct spot. Off to the side, Kurt stands by in tears, witnessing the scene and feeling displaced, hurt, and anxious about what this means for his relationship with his father.

The reality is that approximately 72% of remarriages where both partners bring kids from a previous marriage to the union will fail, according to E. Mavis Hetherington's 30-year longitudinal study on divorce and remarriage. The other reality is that couples beat those odds every day. And they don't do it by buying into the unrealistic, high-pressure fantasy of "blending."