What was the reason her 15-year romance with a psychiatrist ended abruptly with him turning on her out of the blue and calling her a “covert narcissist?”

This, unfortunately, was an alien love bite scenario where he was manipulated to take an interest in her by the extraterrestrials as a way of monitoring her and keeping her in line, and then used that build-up to cause harm by pulling the rug out from under things and making him turn on her. This happens all too often with alien-arranged relationships. It is never a gift to the humans involved, it is always a manipulation that will have a downside eventually, because it is artificially arranged and can be destroyed at their whim, because the love bonds created by the instigator are not genuine, they are manipulated to happen. The love is an artificially-induced impulse, in this case in the psychiatrist, so he is as much a victim as she is because his life was redirected by mind control manipulation to engage in a relationship that turned out to be temporary. That not only gave him the same roller coaster ride as the female victim, but turned him into a perpetrator in the bargain, which will have negative karmic consequences for him even though this was not really his conscious choice. That is the legacy of the interlopers who simply do not care about the havoc they cause human lives.