Just having a partner does not take away your loneliness, mind you!
There are millions of people who have partners, soul mates, who have fallen in love and married the same person, and yet they feel lonely!
Many may not come out and tell you honestly, but if you ask the ideal couples, "Tell me one secret, do you ever feel lonely or anything like that?" They will say, "Yes!" The only people who don’t feel lonely are the ones who are connected with the being, with the self.
One who is established in the self feels no loneliness. Only spiritual elevation can take away the loneliness, not soul mates.