I've played guitar and drums for quite a few years. I'm a master of neither instrument, but I can write my own stuff, play good beats to it, do all the instruments and sing. Maybe they're not the best songs, but at least the drums are good. It's nice to have this independence and not have to rely on other musicians to produce my own demos. I just picked up a 4-track Boss Micro BR digital recorder yesterday.
Believe me, you have NO IDEA what you're missing as long as you don't pick up the drums yourself. I had a similar situation some 1.5 years ago (that's the period I've been practicing drums). I had some orig. material but no drums/drum arrangement. To get better at arranging drums at the PC I picked up learning drums (no teacher so far), for more understanding of a drummer's mindset. My drum arrangements got much better but improving my drum arrangement skills and actually playing/practicing drums are kind of parallel universes in my life. I'm doing them independently, and those are different animals but there is some synergy effect. The point is when I started doing those drum arrangements I was so naive and thought: Well how hard can it be to put some drums over those guitar riffs etc. Boy was I wrong... I learned that the drums are actually enhancing the existing music content by... 30% or something, quite noticeable. EVERYTHING will sound so much better with (fitting) drums. Even with sampled sounds (if you apply enough common sense getting the dynamics right and emulate acoustic drums). And in the result I got drum arrangements which in the end blew me away (I like most of them) but they were so different from what I expected and so "custom made" to fit the specific songs/parts/moods.
What I'm trying to say is that you'll discover a whole new part of "you" if you start another instrument or, as discussed, the drums. Which will make your (music) life so much richer!! I feel more complete as a(n amateur) musician now because the stuff I'm writing now is not longer focused on guitar lines but I'm trying to approach music ideas as a whole, with every instrument being just a component of the whole. And within that concept the guitars are no longer the dominant element while the drums have taken a good portion of bringing everything together.
Also, different drummers will play differently over the same songs. Something I wouldn't have thought possible not too long ago. So if you invest some time to learn the drums (to a degree allowing you to handle them - or a drum arrangement - on your own) you'd have full control of everything, not having to rely on others. Just a thought.