Marriage existed long before the Catholic Church--Abraham was married to Sarah before God first called him and before the covenant between God and Abraham.  And marriage is for here on earth (see what Jesus said about the woman with 7 husbands) that in heaven there is no marriage.  And the Church recognizes that it's the two spouses who perform the sacrament.
Marriage is not an ideal.  It is a path of emotional and spiritual growth (oftentimes very challenging)--at the present time in the Catholic Church limited to laypeople.  But Jesus is the Bridegroom (Jn. 3:29)--and a Bridegroom is vowed to marriage.  What does that mean?