The vows we made when we were wed are viewed seriously in God's sight, regardless of how lightly they are regarded by the world (and increasingly so by the church). Psalm 15 begins by asking who shall abide in the Lord’s tabernacle and who shall dwell in His holy hill. Verse 4 answers, "He that sweareth to his own hurt, and changeth not." In other words, he that gives an oath or takes a vow and then doesn't change, even though it costs him, is someone who is worthy to abide in the Lord's tabernacle. --TBC
"If a man vow a vow unto the Lord, or swear an oath to bind his soul with a bond; he shall not break his word, he shall do according to all that proceedeth out of his mouth."