best version of chart to use for indications of LongTerm

1
Hello,
I have a quick question, maybe someone can help. Years back, a wise older astrologer had helped me with a chart related to my own life and relationship at the time. After the fact, she told me that my relationship with that particular individual was "never meant to be long-term". She had a basis for it, but I am not sure what that basis was. Would one look at a natal+transit chart on the date of first meeting for the "other party" to indicate how long-term or "permanent" something is meant to be in their life? Or synastry? Or a horary? Or their solar returns? (?)
Is there a hard and fast rule where something like that would clearly show up?
Unfortunately I've lost touch with the woman and do not have any references to that past chart (it was over 4 years ago).
But I thought someone might know off the bat where one looks for such things. Thanks in advance.

2
I think contacts between one person's moon nodes and a personal planet of the other is very powerful--it does not have to a so-called positive aspect. I have seen contacts-many times between one person's moon nodes and the other person's venus. My late husband's pluto and south node are conjunct my venus. My mother's south node was conjunct my dad's venus--however I have seen square aspects also. Some Saturn aspect helps, too but too many Saturn aspects can be a negative. AMY

3
Amy thanks so much for the input. I've wondered in the past about nodes because they're not discussed so much.

So then a few perennial questions arise: Does only the node person feel it, or does the node person feel it stronger?
Does there have to be more than 1 such aspect/placement or is 1 enough to make things longer term? And if the "aspect" is separating but in orb, I presume it would still "count"?

Also - maybe redundant question but is Mercury considered a personal planet? To me it always seems so cold and impersonal... Like NN to someone's Mercury, wouldn't it just make communication good but not really a sense of "fatedness" (because I can't imagine there's such a thing as..."it feels like we were meant to talk forever" ?)

4
I am not sure of the orb but I personally would think degrees would be enough. Not sure if the node person feels it more or not. Most of the long relationships I have known with node contacts have been venus/node although I have seen node/mars, I would think Saturn/node might be negative AMY

5
In the situation I have, there is a Sun Node square and a Merc Node square, each within 3 degrees. Would the Sun be negative too, I wonder, being a malefic. My guess is the Sun person would not feel it since the Sun overpowers the node (and any other planet?) but the node person would feel it more strongly. (?) I have no idea though. I wish there were some literature on this.