My husband and I tried anal sex for the first time. We bought an enema for the occasion and I made sure that area was properly cleaned out. We used a condom during vaginal intercourse, but not anal. Three days later the head of his penis and foreskin became irritated with red spots and bumps. He complains about the itch and general discomfort. The only time that goes away is in the shower. Normally I would imagine this could be a yeast infection, I've seen it on him before, but what makes me worry is the fact that I discovered a hemorrhoid on the outside of my anus shortly after his penis became irritated. I'm not completely sure one has anything to do with the other, but the timing would suggest so. I should also mention this is not a common problem for me, in fact I only remember this happening one other time.

Could we have potentially triggered an STD? Is his penis just sore from too much intercourse? Any advice or suggestions?

Yes, you could have triggered something. You don't just "get a hemorrhoid" either. Please see a doctor for this. You should have used a condom in both instances. Different condoms, that is.