I went and asked my husband how he does it. We're a couple since the summer of 2002 and aside from him wanting to chicken out after 6 months (scared to lose his freedom) there has been not a whisper of quitting although we have plenty of fights (of which 99.9% were started by me for stupid trigger reasons -.-).
Here's a flattering self-portrait of him:
1. Before we met he had already been studying Buddhistic philosophy for ten years and he had learned
Ninjutsu (jep, I'm married to an actual ninja :D). So he's calm, he's settled (as in 'emotionally stable and mature'), he can sit through a thunderstorm.
2. He doesn't need me. He loves me and he misses me when I'm gone, but if it were necessary he could let go of me and live just as well without me.
3. He doesn't have any expectations about how I ought to behave, how our relationship ought to look, what I ought to give him etc. Nothing ever lives up to the idealised pictures we create, and thus expectations only ruin the things we get instead of the ones we want.
4. He knows why he's with me. He's conscious of what he loves about me. When I am difficult to be with he reminds himself of the motivation that has been keeping him in this relationship for so long, and that recharges his batteries.
5. He himself suffers from psoriasis and made one big mistake in his life that he's still fixing today; so he knows how dreadful one can feel, he knows self-doubt and he knows how he can cope with that.
To tie that portrait to the way I experience him:
He's pretty amazing, really. I'd have left me and burned all photos of me ages ago. But he's not as perfect as the picture he paints of himself here. He can lose his temper, he can be hurtful, mean, dense, bullheaded, inconsiderate, prejudiced and intolerant. He can do and say things that are unbearable for me.
But - and here's where I'm part of what keeps us together - I desperately love him and I always, always remind myself that he only hurts me out of ignorance and lack of understanding, and not because he wants me to feel bad. I tell him how he makes me feel and try to explain why; there are some issues he still doesn't understand and it drives me nuts, but we're on our way.
Also my self-hate makes me able to eviscerate and decapitate myself in our arguments - that's how it feels when I'm in a triggered rage, everything within me is screaming 'He's killing you!' yet I still try to explain what I am feeling and why and that I know I'm wrong but please, please say I'm right. And he refuses because 'you need to learn to get over that' -.-
Having a relationship demands sacrifices and maturity from both sides.
In conclusion, the receipe for my husband's success as a carer:
Maturity, emotional independence, willingness to learn and a sufferer who's effing determined to stay.