Thank you, I just need to keep reminding myself that there's nothing to worry about. And I'm slowly getting better. But you're right, being insecure and paranoid all of the time isn't a turn-on for anyone!
And you touched on this a bit, but it really boils down to just being myself (and being confident in myself). He's my partner, so of course he wants to see me just being me, doing the things I want, whether it's with him or not. I think we're approaching a good balance of doing things separately vs. together, and I guess in the grand scheme of things, ~1.5 years of dating isn't that long, i.e. we still have time to figure things out! Both of us were pretty novice dating material when we first met, so I'm glad to have made it this far.
Thanks for all the advice so far, Psych Central! You are all a supportive, rational, and kind group to converse and confide in.