What do we give up when we're in a relationship?

Hopefully this makes sense. I would give details about the specific situations inspiring this question, but it’s lengthy and intricate and kind of knotted-about in my head, so I’m pretty sure whatever I’d put out would be more jumbled and tedious than anything… I haven’t seen too many successful relationships—the “giving up” that I’ve seen has been (or at least seems to me) more harmful than it’s perhaps worth: giving up convictions, passions, pursuits, needs, autonomy, identity… But then, relationships are, at least in part, an act of compromise—even in successful relationships, we’re giving something up, aren’t we?

If you want to share, what have you given up in a relationship, and what has been the impact? Or, in the abstract—what do we give up, and to what effect(s)?