Is it not common to make compromises in most human relationships?
It happens even in the best relationships, in families, in friendships, etc.
It seems like there are lots of rules, especially the unwritten kind, surrounding dating.
Well one can start with a platonic relationship. My wife and I met through mutual friends. I just started talking to her, and did not ask her on a date until about 9 months after I met her. We dated 3 months, when I proposed, and we more or less lived together for one year while engaged.
If there is an aspect of commitment in the relationship, do you not give up anything in making a commitment? What exactly?
I suppose one gives up total autonomy, in exchange for a committed, and hopefully reciprocal, relationship.
Does the "you're free to do whatever you want to; I don't expect anything from you" approach actually work in a long-term, presumably rather rare, intimate relationship with someone you care about?
Not from what I have seen. Both partners have expectations. That is where communication comes in. I know what my wife expects and she knows what I expect - as long as we communicate.
Does no one expect their partner to live in the same house with them?
I know of several relationships where this is the case.
To stay home and raise their children?
This must be by mutual agreement. My wife stayed home for a few years, and when the kids were old enough, she went to work part time, and gradually increased hours as the kids matured and were more independent. If I could have, I would have liked to stay home and work part-time.
To spend x amount of time with them?
I am usually home most evenings, when not traveling. I would prefer to be with the woman I love, by choice, not on demand.
I am growing old together with my wife, who is 6.5 years older than me. I think she is attractive no matter what.
To stop looking for another partner?
Of course. Although since I have been married, I have found two other extraordinary women, either of whom I would have married had I know of their existence 25+ years ago, or if I was not now married, I would marry either one if they were interested (and actually one was interested). But I am not looking to change partners.
Maybe it would help to ask it this way: If you were in a serious relationship with someone, what could they do that would be a rather major, shocking disappointment?
If she tried to kill me, e.g. run me over with the car or strangle me in bed, I might have a problem with that.
Seriously, if my wife was violent or abusive, I'd leave with the kids. If my wife engaged in criminal, hurtful or otherwise destructive behavior, I would seek help, and then perhaps leave if she could not stop such behavior.
Actually, my wife did hit (punch) me in the mouth one time (about the time we got married), more or less by accident. She got frustrated when she could not stick a banana label on my nose, after I did it to her. She struck out in frustration (not really deliberately or out of meanness). She cried, I laughed - because she told me if I ever hit her, she would leave - and her she was the one who hit me. She has a really good right cross, and I had fat lip and bloody nose. I took her in my arms, and kissed her and told her that it was not a big deal to me - and that I loved her.
She only hit me once after that out of anger, and I pushed her away at that point. I have never hit my wife.
For example, if your partner told you one day that they didn't want to have sex with you anymore, you wouldn't bat an eye?
I would want to discuss it, and then take it from there. That would not necessarily end the marriage, but it might cause some tension.
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Male egos are far too fragile to handle being told something like that! 
) of friends, family members, and pets. 
I think you're a fine woman.