I definitely don't think you are weird at all for not wanting a bigger ring! It's very thoughtful of your SO to want to upgrade.
I'm kind of the same way as you...I told my FI that I've always wanted a modest looking ring, nothing larger than a one carat, and definitely a plain, "non-diamond" band. I got engaged a few weeks ago, and he kind of respected my wishes
. I love the ring that I have, and really don't ever see myself upgrading to something larger.
Good luck!
I'm kind of the same way as you...I told my FI that I've always wanted a modest looking ring, nothing larger than a one carat, and definitely a plain, "non-diamond" band. I got engaged a few weeks ago, and he kind of respected my wishes

Good luck!