The word πράγμα (= thing) has a very general and broad meaning in Greek.
Two of its main meanings are:
1.Everything that we can see, touch or feel.
Nα μαζέψεις τα προσωπικά σου πράγματα = Clean up your personal things.
2. Something that happened at a given time or a certain circumstance.
έτσι έχουν τα πράγματα = this is how it is (literal translation = this is how things are)
Within the first meaning (something that we can feel), the word "πράγμα" can refer to love between married couples.
Η αγάπη ανάμεσα στα παντρεμένα ζευγάρια είναι πολύ σημαντικό πράγμα. = "Love between married couples is a very important thing."