I highly recommend Amigos Del Mar. The Discover Scuba aka Resort Course will be such a blast, he'll be hooked for life.
You start with a video (Water, it's everywhere) then you get into some shallow water to learn how to use the equipment. You learn how to clear water out of your mask, equalize the pressure in your ears, and breathe with a regulator. Then it's off you go for a fairly shallow dive (our first was probably 25') the Dive Master will be right by you the whole time. You'll probably have a lunch break, then do a second dive.
When I went, I was a newly certified diver, but my friend had never thought she would dive in her life. We were both so thrilled afterwards even though we both confessed that we were scared to death right before we went in.
I hope you'll join you boyfriend and have an experience you'll never ever forget.