“How do we know whether or not our exes are genuinely interested in getting back with us, or just want a P&D?"This is a revealing insight into the female mind. The fact that the man cares about her and is genuinely interested in a relationship with her is completely outweighed by the way he carries himself in front of her. This is why all the romantic gestures and vows of eternal love tend to avail the average delta and gamma so little. Women find loyalty to be a positive trait in men, they simply do not find it to be an attractive one.
If, when they approach you about getting back together, they come across as confident, desirable, sexy and having their shit together, then they probably just want a pump n dump. If they come across as needy, desperate, undesirable and basically just a wreck, then they are probably serious and really miss you.
"Hah…so it’s a no-win either way."
The way women initially view loyalty in men is rather like the way men view a woman having an impressive degree or a good job. It's nice and perhaps even worthy of respect, but it simply has nothing to do with whether one is going to find her attractive or not. That doesn't mean that a man's loyalty isn't valued once the relationship starts, only that it isn't going to somehow convince a woman to be attracted.