Just my 2 cents, but I think sex is important. It allows for a level of intimacy you just can't get otherwise.

I'm not saying you can't be intimate otherwise, of course not. But what better way to be close, connected, and truly intimate with someone, than to trust and love someone enough to allow them to touch you in such a private way? or to allow them to pleasure you, or vice versa? I have never had feelings that did not otherwise go to another level after having sex with my partner.

It's not required and certainly shouldn't be THE most important thing in your relationship, but taking intimacy to that deeper and more personal level is something a lot of people need, both mentally and biologically.