Why is this a theme for me?

So, a few weeks ago, I blogged about the repeat imagery that crops up in my writing (tuna fish and mayonnaise, paper umbrellas, and, of course, water, to name a few).

Yesterday, while I was swimming, I was noticing the themes that repeat themselves in my writing. Themes I seem not to tire of exploring, that creep in, even when I'm not expecting them to -- in both my women's and my young adult novels:

Friendship, and particularly, the betrayal of friends, especially female friends;

Surface beauty vs. inner beauty, and whether you must give up the effort to maintain one to achieve the other;

Marriage and infidelity, and how the latter affects the family unit.

Of course, these themes are universal, so not hugely surprising for me to write about, but still interesting how they always pop up. The first personally affected me -- in h.s. my closest girlfriend betrayed me in a swift, cruel act (that was borne of a moment of weakness on her part rather than sincere, and I long ago forgave, but which certainly shaped me and my trust toward women at that time); the second played itself out over and over in my family growing up; and the third not only is a common issue for anyone in a long-term marriage (mine is going on 17 years...), but is a focus of my "paid job" as a divorce mediator, and before that, a divorce attorney, so permeates my waking life.

What are the themes that drive your novels? Do they crop up time and time again?