Short answer - not sure. I think we married too quickly, I know I was looking for some security after a traumatic couple of years. My first marriage lasted just 3 years (he'd not been married before). We had some ups and downs in the early days and nearly split up twice.
I've known him about 42 years, couldn't stand him when we first met!
We've now been together for 37 years, married for 35. I suppose after all this time our marriage is a bit like a pair of tatty old slippers that are falling to bits but still comfy and you don't want the effort of finding something that might be better. There must be something in it though, as we've been together for so long.
He's still not fully housetrained (leaving dirty clothes everywhere etc) and I find him very annoying if we are alone together for extended periods. The washing machine is still a mystery to him but he does his own ironing.
On the plus side he is very calm and I've never known him lose his temper (he's the broody, withdrawn, sulky type). He will do housework when prompted (and sometimes I don't even have to ask twice!) He's got a generous spirit and I've never known him be nasty to anyone (except perhaps a sister that we are now NC with). We are similar intellectually and sometimes seem to have an almost telepathic understanding (or does that come with spending most of your lives together?)
Astrologically, we're a water sign and an earth sign - which together make mud! We're probably the boring most unexciting couple you could imagine.
He's not very romantic, and above all that's the one thing I would change.