I apologize in advance if this sounds a bit harsh (I'm using the generic you; not meant as a personal attack, but your post brings it to mind
), but this is kind of a pet peeve. I guess I don't understand the insistence on using the group guide as a dive buddy. Aside from the safety issues (divided responsibilities), I see it as poor form relative to the other divers in the group. You aren't the only diver that hired the guide. Nothing is free as in "free guide." If there is a guide in the water, the group pays for him one way or another. The rest of the divers, if they choose to follow the guide, have expectations of the guide that don't include your buddy needs.
If you are diving alone then it's your responsibility to procure a buddy. That process should start as soon as you know you'll be diving alone. ... My experience is that divers are a pretty amenable bunch if approached in a friendly, forthright, intelligent fashion. After all, most have been in the same situation at some point and it's not an unusual request. Don't wait until you get to the dive site, then raise your hand and say I don't have a buddy. It puts the DM/guide in a bad situation. It also shows poor planning and a lack of situational awareness on your part, both anathema to finding willing dive buddies. At that point I'm prepared to raise my hand, vote for a shark dive, and use "that guy" for chum.
Divers in general are pretty helpful and easy going (especially on vacation) as long as they don't feel taken advantage. Dive safe and be respectful of the others on the boat. All IMHO.