At 43, I've been married since 2005, reasonably happily so. It's not fireworks, but fondness and caring, kisses and hugs. And I love my wife. We have two kids, now 12 and 14, who occupy our thoughts. I think we'll have a serious conversation about the future with my wife once both of them go on their own, but I doubt either one of us wants a change then.
See, marriage is a commitment. You make a choice: this is the horse you're betting on - figuratively speaking of course :-) - and you want to see it through, thick or thin. Of course, you don't know how it will work out in the end, but the mindset must be clear at the outset (commitment). There are many reasons to commit like this, and love in the blind sense is just one of them. I hate to admit it but with age, I'm beginning to understand the rationale in having the family decide who one should marry...
I've had a couple of brief crushes during our marriage, but nothing serious beyond occasional flirt. I think the key is to date as much as possible when one is young to get an idea of what it would be like with others. I did this, and realized that nobody is perfect, including myself of course, which helped me commit to the best match.
Good luck.