Lust doesn't go away in a long term relationship. You just have other things too. I think sometimes they become part of the furniture and then at random times it's like you really see them again properly and all the emotions from when you first met kinda rush forward. You feel more attracted to them, lucky that they've picked you and just really in love.
It can't be like that all the time. What's sexy and loving about laundry and the mortgage? But you do get moments where they're cooking the dinner or they've done something nice and you just get that moment of, I'm so glad I'm with you.
I don't get bored. At least once a day my partner makes me laugh so hard I worry about peeing myself! Some days we talk less but it's comfortable silence.
It's okay if you're not in the place to want that kind of relationship. We mature and want different things. We look less for people to fill particular gaps in our life for us.