I’ve heard that if couples are married long enough, they start to look like one another. I’m not sure if that’s true, but I think couples do often look like the other couples they hang out with.
It may feel more comfortable to be friends with someone who’s just like you, but you’re depriving your marriage of a great chance to grow. Maybe the couple you spend the most time with is also newly married, or is raising teenagers, or is retired.