"Someday, some little girl who's probably not even born yet is going to steal you away from me, and I hate her already."

No, I didn't say it and I don't remember even thinking it when my son was born, although when I met my future daughter-in law, something similar may have flitted around in my head. Echoes of that time reverberate in my coaching practice for parents of young adults when clients discuss their grown kids' upcoming or recent nuptials, and their efforts to accept the Other and adapt to their new role in their child's life.

It's one of those significant life events, and everyone responds differently, viewing it as either a personal gain or loss, but in either case, determined to do the best they can to support the couple.

"Do I wish she'd married someone else? Absolutely. But do I want her to be happy? Of course. I just can't stand him," said a client. Another, with more pressing concerns, was pondering what to do about offering his son's partner a job in his business and how it would impact both his family and his firm. And a third was arguing with her husband about attending a lesbian daughter's wedding.

Their choices aren't ours

Research into parental control over their offspring's mating decisions has mostly been focused on an evolutionary psychology theory. According to Menelaneos Apostolou, a leading researcher in the field, parents have vested interests in their children's marital behavior. Accordingly, they employ a battery of tactics to manipulate the mate choices of their sons and daughters, which vary in effectiveness.

Evidence from independent studies indicates that parental manipulation has an effect which is nevertheless small, with some tactics more effective than others. Researchers also found that parents have a good idea how effective their attempts at manipulation will be on their children's final choices.

There are cultures in which arranged marriages are the norm, and no doubt, the wishes those parents have for their kids are much the same as they are for us, though they may be better at wielding their influence than we are. But all of us know we can't choose who our kids love. In marriage, as in everything, we want the best for them. And their choices aren't ours.

Be considerate of their needs as a couple

I remember how my mother responded to the news of my elopement to a man she thought was wrong for me. To me, she said, "You can always come home if you want to," and to everyone else, she said, "Isn't it wonderful? Yes, we're having a party for them, please come."

She found things to praise about him, like his manners (which were excellent) and his charm (which was considerable). And to her credit, she only actually said "I told you so" a few times when both wore thin.

I was more discreet about my own daughter-in-law, and approached her warmly — or so I thought. Only my own daughter sensed I was less than wholly enthusiastic. "I can tell you don't like her," she said, "but nobody else will [notice], including my brother."

And so I learned by doing; by focusing on how happy she made him, by stepping out of their way and being thoughtful of her needs, by maintaining the degree of closeness and distance they, as a couple, managed. In some ways, it was better. She managed our relationship as a family in ways that curbed my tendency to trespass on their boundaries and I was included in their activities and consulted before decisions about holidays were finalized.

We were never emotionally close, but when she and my son divorced, I was truly sorry for all of us. In the many years since, she and I have become remarkably intimate friends; we have my grandson in common, as well as a variety of interests and talents that continue to surprise me. We've both grown up and gotten over ourselves, is what it is. I still haven't curbed my tendency to write about my family (sorry, Jen). I call her, like my former son-in-law, mon putatifs, which is French for my putative, or "as if" family members.

Keep an eye on boundaries

There are obvious ways to be a good in-law, most of which involve reconciling your boundary style with theirs; that is, let them, individually and together, regulate the distance and closeness between you. That goes for not demanding their presence at every holiday; proffering your advice unless, and only after, they ask for it; refraining from expressing your judgment on their choice, taste, lifestyle …you get the drill.

It means not taking sides, even when it's obvious who's at fault. Don't let your feelings get in the way of theirs. Be a sounding board if that's what they need. But otherwise, just offer them comfort, shelter and a respite from the storm if they need it. And then get over it, which they will regardless of the advice you couldn't help giving, without carrying grudges.

If, as a single parent, you've been particularly emotionally close to your grown child, it's especially difficult to respect their couple boundary without feeling shut out of the intimacy you once enjoyed with your daughter or son.

It's also hard to see your grown child as a member of a whole other family; "For so long it was just the two of us, and I felt so diminished by her fiancé's big, close-knit family," said one client. "But they welcomed me into their clan, and I'm thrilled."

One final thing to remember from your seat right behind them as they're exchanging their vows: Smile like you mean it. Or, as my daughter said when my son got married, "Just wear beige and keep your mouth shut."

Jane Adams is a social psychologist and coach based in Seattle. This article originally appeared on NextAvenue.org.