Being in a relationship is great. But being over-possessive in a relationship is very bad. It is destructive and it gradually weakens the bond.
Every person should be given their own freedom, allowed to cherish their own individualism. Because we all were born free, without anybody to accompany us. Now when someone suddenly comes and imposes himself upon you, you feel claustrophobic, as if your freedom is being willingly snatched away.
There is always a thin line between being a protective lover and an over-possessive partner. Yet sometimes we confuse them and think that they overlap each other. From being a protective partner, we do not realize when we turn into an over-possessive one.
Also, there is someone who is innocently possessive and someone who is very aggressive. Over-possessiveness can also lead to extreme physical and emotional abuse, which can destroy your togetherness completely.