b1gcountry:
IMO, you should not have separated from her to go tell the DM; you should have ascended with her to your safety stop, and you should have just stayed above the DM. He would have noticed you there, doing your stop. If the instructor with whom you are doing your DM training always wants you to advise him when you take a student up, that is an entirely different scenario - isn't your wife a certified diver? As such, in the incident you mentioned, you are not DM/Student being supervised by an instructor, but rather a buddy pair who should remain buddies. You're not a DM candidate at that point, but you are your wife's (more experienced) buddy. Put yourself in those shoes for a minute - you have around 25 dives, are counting on your more experienced buddy for guidance, and suddenly he disappears and heads off with someone else. Is it possible that at that point she simply did not realize that you were going to signal to the DM, but thought instead that she was being abandoned? And when you did reappear, her panic related to the abandonment contributed to her buoyancy issues (possibly her "slow deep breathing" got all screwy) and resulted in her grabbing onto you so you couldn't leave her again?
I am part of a husband/wife buddy team - or former buddy team, I suppose, since we are now both instructors and rarely dive together anymore, it seems. We dove together almost exclusively for three years, and developed a great buddy rapport over that time. Although we started diving near the same time (he started shortly before I did), he was, IMO, a much more confident and better diver from the beginning. On our first "great" dive, which was in quite a wild current, I spent about half of the dive clinging onto his hand in a vise-grip, similar to what you noted at your safety stop. In retrospect, I know that made his dive much less enjoyable than it would have been had he been alone. From my perspective, I wanted to ensure he was there, whether I needed him or not - so I held on. We had at least one incident where we had a fairly major miscommunication that resulted in angry words when we surfaced - it is difficult to clear up miscommunications underwater, so I encourage you both to be patient, and remember all the good things about each other while you're down there. Presumably your wife is not crazy or irrational; it's unlikely that she becomes so underwater. Also, assumptions about understanding can be very dangerous. Maybe get yourselves some slates, and communicate that way to start with. I can tell you that after six years of diving with my husband as a buddy, I either understand clearly what he is trying to communicate to me, or give the shoulder shrug and trust that if I don't understand, it will be okay and just follow along. If one of those things isn't true, I whip out my fisher-price slate and write a big question mark.
When you say "she doesn't listen when I tell her what we're going to do" my wife-hackles rise. JMO, but it sounds like you are not participating as a "team." I understand that you are more experienced, but really, so what? Remember, this is not a DM/student relationship, this is a buddy/buddy relationship. Do YOU listen when she tells you what you are going to do?
Your suggestion that she dive with someone else for a while may have some merit. When my husband went to do his DM internship, I was buddyless in cozumel for five weeks. I was the "extra" on every boat, and dove with a wide variety of people, some less experience than I, some more experienced that I was. That time without my "regular buddy," who I may have relied on too much for my own good, was a period of tremendous personal growth as a diver.
However you choose to proceed, good luck, and have fun!
kari
