Be nice to know if this is the chart of a woman or a man.
Not necessarily. But ....
Put the shoe on the other foot...
Remember that their chart shows "you"...the one that fulfills their partner role.
A chart shows "how I am", but it also shows "how my partner is" (the type of person I'll attract and/or be attracted to.)
I knew a woman with Venus opposite Neptune (Taurus-Scorpio, 2nd-8th) and it was simply not in her nature to be a one-man woman. With plenty of Aries in the chart, she was "adventurous" (adventurous means that, like a young child, she picks up one toy, quickly tires of it, moves on to another...nature of Mars). She was also dependably honest, a trait which has a lot to be said for it.
You must look at the whole chart. Making such a judgment ("fidelity") based solely on the Venus square is questionable practice. Taken alone, this configuration would tend toward an open relationship.
As to the type of relationship..."interesting", "unpredictable", "experimentative", "sensuous"