"God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us". -Romans 5:8
In God's eyes, the ideal marriage is one in which you don't tell your partner "I love you because..." but rather "I love you, period."
3 types of love make up a great marriage: phileo (friendship love) and eros (sexual love). Agape is "sickness in health love".
The only way love can last a lifetime is if it's unconditional.
The truth is this: love is not determined by the one being loved but rather by the one choosing to love.
Unconditional love, agape love, will not be swayed by time or circumstance.
do something out of the ordinary for your spouse - something that proves (to you and to them) that your love is based on your choice & nothing else.
Demonstrate love to them for the sheer joy of being their partner in marriage.