Ronia
Its a Combination of many things actually. But the moon sign in a mans chart explains alot. If his venus sign and moon sign Are not friendly energies then you have a wild card. In most cases he May be attracted to a certain type but will 'wed' someone completely opposite. The health and stability f his 7th house will give you alot of clues.
I am one who doesn't believe in the Moon/Venus signification in men's charts. IMO, of course. One of my closest friends has a conjunction Venus/Moon in Cancer of all places! In theory he should be a very homey oriented man who seeks both a lover and a wife in one woman who is not supposed to be flamboyant, ambitious, or too bright, lol. He doesn't. He is indeed as wild as it gets and seeks something completely different. And there is a reason for that and indeed it is in his Sun, position, and aspects. Another close friend has a Libra Venus ruler of the Ascendant !!! as dignified as it comes, in a great house, with only one aspect which is positive and from the Moon - he is the most difficult partner I have ever seen and I feel sorry for his girlfriends, there is nothing harmonious about him. And again, there is a reason for that in a stellium around his Sun. Which is why I'd say there is a whole chart to look at and no planet should be ignored because if we rely on one or two, we will be wrong, 99.9% of the time, IMHO.
I have many other examples about failure of Mars/Sun in women's charts and Venus/Moon in men's charts and there is always a reason for that in the other planets and their aspects.