Lyric discussion by Kalebrodavstheworld 

To me, it's about the questioning and doubt that comes right before you walk down that aisle in a marriage.

The speaker isn't ready to marry this person, and she can't say with certainty that life with them is going to be great, although prior to this, she thought she could ("I can't see the future though I thought I could see").

She begins to think about leaving this person, but doesn't want to because of the connection they've made. She loves him (even if it hurts) but isn't ready for marriage.

The title, (as well as the lyric) 'I Still Do,' seems to be a play on words, with the last vow in marriage typically being "I do."

My Interpretation
Negative
Subjective
Fear
Doubt
Marriage
Uncertainty
Love
Commitment