Left the church 8 years ago. I've been with my nevermo partner for 6 years.
We have chosen to remain unmarried. Mostly, I influenced this as I never wanted to go thru another ceremony again with all its religious and patriarchal implications. We could go to the courthouse and sign a piece of paper, but:
*With our salaries, there are no tax perks. In fact, we'd pay more than if we both filed as single.
*We have legal documents for medical purposes, and we've named each other as our beneficiaries on all financial accounts.
*My commitment in my heart is reflected in my actions every day. We have made a commitment to each other that we will work hard every day to choose each other or be honest with ourselves and each other if we find we are growing in different directions (without judgement). Despite our work travel schedules, we have many ways we stay close and connected.
A marriage certificate does not keep a relationship from ending. The question may be whether you want to be in a a long term, committed relationship (regardless of wedding/marriage) or whether you prefer a more casual relationship.
Commitment may or may not come with a wedding or a signed certificate of marriage. What is most meaningful to you is what matters.