Teaming up is important.  I always wonder why so many are single. Perhaps we need some social construct between "roommate" and "mate".

roommate with children?

Why is it that middle age is so isolating?

And while its effects may be felt by those who remain single and find their support networks weakened as their married friends become less available, it hardly serves the married that well either, as recent articles on the difficulty of making and maintaining friendships in (married) middle age attest. No wonder people whose spouses also happen to be their best friends get such a greater benefit from marriage than others. For some, this particular “super-friend” may well be one of the onlyclose friends they see with any regularity—it helps to really, really like them.

Looked at from that angle, the fact that marrying your best friend seems to make middle age “slightly less terrible” (as the headline of the Washington Post’s coverage of the study sardonically boasts) seems less a ringing endorsement of marriage than an indictment of the way many of us spend ourmiddle age—in socially isolated domestic units, each consumed with the nearly impossible task of balancing work and family, made bearable only by having a close friend in the trenches with us.

1) childcare/babysitting is hard to come by unless wealthy

2) not enough time to try to thrive at work, parenting, marriage, friendships, etc.

Basically all of the biggest responsibilities are packed together at a time when time and money are tight.