I was in panic mode when I wrote the above thing yesterday, but writing it all out inspired me to communicate these feelings to my sweetheart, and he was surprisingly open to it! So, yay!
Here starts adventure, I guess! I feel so relieved...
I got him to agree to start going to talk to a therapist, too, just because it's so hard for him to get out what he needs to get out, and so we will both have a good frame of mind when all the needs for constant reassurance and communication come up.
Life is beautiful.