What right has the government to tell us what relationships we can have?!?

i think d govt. is nt concerned about any indivisual or his or her marital status as much its supposed 2 concerned about d consequences.......wen dey make a rule like dt, dey keep d repurcussions f d mattr in their mind......dey kinda think wt such a decision may lead 2 in a society.......mor disturbances....more fights.....laws regarding inheritance, marriage, divorce......etc....become more complicated.....they keep d whole picture in mind b4 dey cm out wid such a decision......