you would Marry because Love. Love is related to Spouse. Spouse is a type of Relative. Ancestor is a type of Relative. 
Tomato is a type of Plant. Plant is related to Like. 
Marry --MotivatedByGoal--> Love <--RelatedTo--> Spouse --IsA--> Relative <--IsA-- Ancestor 
Tomato --IsA--> Plant <--RelatedTo--> Like 