Welcome to fishlore. I had a very similar episode with my two German Blue Rams. After loosing two Golden Rams a few months back, I replaced them with these two. I thought I had a male and female but now that the colors are "Coming Out" (no pun intended) I think they are two males. They started hanging out together when I first got them, now they either chase each other around or usually have a plant of
driftwood between them. Adding one female may not be the greatest idea, you have plenty of room to add a few females. The one inch per gal rule, you're only at 10 inches. Leave some room for "maintenance fish" maybe some catfish (I personally love corys), also later when the algae starts you will need a small pleco or a few ottos. I keep a lot of maintenance fish, i think that's the secret to having clean/clear tanks.
I would also get a few more neons so they school together... it looks nice.