It is said that the groom keeps his bride on his left side to be close to his heart, and also so he might defend her from any form of aggression if need be.
“And the Lord God caused a deep sleep to fall upon Adam, and he slept: and he took one of his ribs, and closed up the flesh instead thereof; And the rib, which the Lord God had taken from man, made he a woman, and brought her unto the man. And Adam said, This is now bone of my bones, and flesh of my flesh: she shall be called Woman, because she was taken out of Man. Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.” – Genesis 2: 21-24
“Set me as a seal upon your heart, as a seal upon your arm; for love is as strong as death, jealousy as cruel as the grave; its flames are flames of fire, a most vehement flame. Many waters cannot quench love, nor can the floods drown it. If a man would give for love, all the wealth of his house, it would be utterly despised.” – Song of Solomon 8: 6-7
“For no man ever yet hated his own flesh; but nourisheth and cherisheth it, even as the Lord the church.” – Ephesians 5: 29