Despite the logic of this, a man does not do the smart thing. He feels so compelled to show his family and all the world that marriage has not changed him, that he insults the institution of marriage. How would he feel is his wife acted like she was single just so that her family and friends don't feel “left out?” When you marry, the rest of your circle is going to feel a little left out. If your circle can't handle it, it's time to find another circle, or go back to staying single.
I think if more men acknowledged that they're happy with their wives as they are and that their marriages are important/indivisible/irreversible parts of their lives, they would find that other people respect their marriages/spouses. The women don't seem to have too many problems making boundaries with their own families; I think it's because they acknowledge that their marriage is an important part of their lives. As for parents, they're all very nice in their place – outside your marriage.
I truly believe that all people should be grateful for kindnesses received, but giving birth to and raising a child – though a formidable task – benefits both the parents and the children. In different ways, perhaps. But it does benefit both. How does one express gratitude to someone for bringing them into existence and caring for them? I think this is an impossible task, because nothing you do can measure up. Just as nothing a parent does can compensate for the joys, challenges and learning experiences and social recognition that having children brings with it.
If they visit you, be as considerate towards them as you would be to your guests. If you visit them, be as considerate towards them as you would be with any other host. Being their parent does not give you the right to be fussy or mean. Resist the urge to parent once your kids are grown up.
If you had any real concern for your child or his/her family, you would not be making life hard for them. This is the kind of behaviour that is the one way ticket to a breakdown of relations between your child and his/her spouse or between your child and you.