One of the main challenges B and I have had in our relationship is in working together as a team. This seems like a pretty obvious part of marriage: it's mentioned in most marriage vows, you are legally considered as one unit (for instance, you can't be required to testify against your spouse), all money and debts belong to both spouses... But for me it's been a struggle.
Being on a team is of course nice (security, companionship, practical support, division of labor, etc), but it comes with a big downside: you can no longer be independent. In fact, the main problem with being married is that your life no longer really belongs to you.
You can still do pretty much anything you feel like, but now with one great caveat: you must get someone else's permission. This doesn't mean that I always have to ask B, "Can I buy this potato, please, honey?" But it does mean I always have to act like I am asking this question (would this be OK with B?). And he has to do the same. This isn't because someone came down with a rulebook and imposed the law on us; it's for purely practical reasons. We have tried (many times) over the course of our relationship to act differently, where we each make our own decisions and "follow our bliss" and so on. It's always been a complete disaster.
Because marriage is such an intimate relationship, anything I do will have an effect on B. Even something as petty as eating all the bread for a midnight snack means that there won't be any sandwiches for him the next day. I can't "follow my bliss" freely, because by doing so I am necessarily ruling out many possibilities for B. Actually I can't even eat (or sleep, or buy stuff) freely, for the same reasons.
I frequently find this aspect of marriage maddening. I don't want to think about other people all the time, and I hate the feeling of responsibility that comes with this. I can't even eat ice cream if I feel like it, because it makes me sick, meaning I can't fulfill my responsibilities well, meaning I am a bad wife, meaning B is affected...I am no longer fully free to chart the course of my own life, as now I have a co-pilot with his own (frequently entirely different) opinions.
No man is actually an island, but as a modern American it often feels like it. We don't generally stress our responsibilities to others, or our interdependence. The very idea of a "self-made man" is the complete opposite. But in marriage there are no "self-made men": any success or failure I have is B's too, and vice versa. This scares me: it's like tying yourself to another person as you climb a mountain. If the other slips, you will be in a world of trouble. The dependency, and trust, involved is really frightening.