Jupiter in astrology means to grow big. It like to expand things. Pluto is obsessive compulsive, it’s an irresistible urge. Composite Jupiter conjunct Pluto promises success, power, wealth to the relationship.
Venus means beauty in Astrology. It is your attraction to what is beautiful. Pluto is compulsive, irrational and it is your obsession. So Venus square Pluto in the Composite chart means the couple are irrationally drawn to beauty. A tendency to be devoted to each other.