I believe you may have gotten a very wrong impression of what a "dive buddy" is.
What you're describing is a Divemaster or even an Instructor.
A dive buddy is literally just that - a person that you dive with on a particular dive. There's absolutely nothing special about a dive buddy.
Sure, you're supposed to look out for each other, but ultimately, every diver is responsible for their own safety as well. A dive buddy is primarily there for situations which need the help of a second person, such as entanglement or a medical emergency, (the oft-quoted and trained for out-of-air emergency is something which should NEVER happen to a diver unless there was an equipment failure), and often just to contact surface support and try and get help asap (always depends on the relative level of training of the people, a Rescue Diver is (or at least should be) a lot more competent buddy than another OW diver, for example).
As someone mentioned just above, even if you have no intention of ever diving, especially after your tragic loss, it might be very useful for you to do the Open Water course, just to learn a bit more about scuba diving and the culture of safety that is, or should be, ingrained in every diver.