Well, not so much a structure, in chemicals perhaps, especially oxytocin. The TED talk on 'The moral molecule' is really interesting, if you haven't seen it. It made sense of a lot of my life, philosophy, attitudes and feelings!
well there's another saying "emotionally stable", but i would associate structure to what we can control, which we can't as we can only control what happens from ourselves, not what is happening around you, it is more of a balance, between chemicals