As it happens on skyscript I just recently gave a summary of Bonatti's technique on unfaithfulness.
This is just a quick simplistic summary of course.
Really the idea of unfaithfulness can be summed up easier than Bonatti perhaps words it. By quesited below I mean either the Moon or Lord 7, unless I specify one in particular.
The wife is unfaithful if:
The quesited separates by less than 3 degrees from another planet, provided that planet is not the lord of the ascendant - she used to be unfaithful but isn't any longer.
If Lord 7 is with the South Node, and not aspecting anything else, she has been unfaithful.
If the quesited were in aspect to a planet which is itself within orb (or perhaps by whole sign) with both Mars and the South Node she is unfaithful
The the quesited is conjunct Mars by whole sign, provide the SN is not in this sign, then the wife is unfaithful.
If the Moon separates from Mars, provided Mars is not the querent, then the wife has been unfaithful but their affair is over.
If the quesited were joined to a tripicity lord of the ascendant, then she has been unfaithful.
The wife is faithful if:
The quesited and Lord 1 are in aspect (provided no other planet is closer).
The quesited is void of course.
Lord 7 in aspect to the North Node, particularly whole sign conjunction, provided no other planet is in aspect, or at least closer in aspect.
If Mars is Lord 7, or Moon is Lord 7 and received by Mars, then she loved another but nothing came of it and she has not been unfaithful.
Now provided none of our rules for determining that the wife is faithful are present, we can speculate that the wife lusts after or is in love with another - thought his love may not be reciprocated and so she may not have been unfaithful. Our planets here are, for example, Jupiter, Mercury and Saturn, and to a lesser extent Venus.
If the two planets are in aspect (the quesited with the above planets), presumably by application, then if they are in mutual reception, there is a strong likelihood of something happening between them and the wife is likely to be unfaithful - unless the opportunity hasn't arisen yet - but both want it to happen either way.