Satchel Paige has been attributed as saying "Work like you don't need the money, love like you've never been hurt, and dance like no one is watching." Truer words have never been spoken.
The relationships that work are those that aren't characterized by, or plagued by, comparisons to past relationships or expectations for the future, but live in the moment. Relationships that thrive and grow are those that focus on the now and ignore the past (that is, the past outside the relationship - remembering the pleasant past time of this relationship builds the now) and also don't dwell on the future and place expectations that might or might not be fulfilled.
I believe that God has at least one perfect relationship planned for all of us. For some of us, that might be a relationship with Him rather than another human being. I don't believe that all of those perfect relationships are necessarily destined to be marriages. In addition to perfect romantic relationships, there can be beautiful friendships (Rick and Louis at the end of Casablanca...for the confused modern, I can guarantee that Rick and Louis didn't just discover they were homosexual!), and there can be transitional friendships (friendships that God puts in our path to help make us, or the other person, ready for what God has planned next).
My first marriage is a perfect example. Neither of us were ready for a committed relationship, and the relationship was a disaster. But it also produced two wonderful children and the experience prepared both of us for healthy and lasting marriages that would come later, and from these perspectives it was still a perfect relationship. I don't believe that God intended either of us to experience the disaster, but He made use of the mess we both made after we'd made it!
Some indicators that you may be misunderstanding the relationship you're in, or it may be intended for an end other than what you've anticipated:
- If you know more about the other person's past relationships than just names, then your relationship may not be intended to end in marriage. The other person may not yet be healed of those relationships and ready to move on and invest fully in a new relationship. You may be destined to participate in that healing, possibly in a perfect friendship as "best friends". (As a sign God likes being efficient, He often puts us into these relationships when both parties need healing to be able to move on.)
- When you talk about the other person's family, if you talk more about what makes them dysfunctional than what makes them special as a family unit, then you're not in a relationship, you've become a therapist.
- If the other person wants to talk more about themselves than they want to talk about you (both meanings - you as a person and both of you as a couple), then you're probably destined for a perfect friendship, because they aren't yet selfless enough for this to be a perfect marriage.
- If you can list reasons why the other person is so right for you, then the relationship probably isn't destined for marriage. Every one of those reasons is something that could change, and leave you dissatisfied in the future. (My mother in law tested me with a "why do you want to marry our daughter" and I thought I was sunk until I realized that my "I don't know, I just do" was the right answer.)
- If you can imagine yourself ever being with (or wanting to be with) another person, yes ever, imagine a set of circumstances other than death in which you'd be apart, imagine anything other than the grave that would separate you, then the relationship is not destined to be a perfect marriage.