Maintain Other Relationships
Although neither of us is involved in romantic or sexual relationships with other people, early on we committed to paying close attention to our friendships. We don't want to be the couple that can't go anywhere without each other or that spends every waking moment attached at the hip.
Keeping other relationships healthy is one of the ways that we make sure our relationship doesn't get stale. It also gives us a healthy personal and love life balance. We have some couple friends who we enjoy spending time with together but we also have our own friends that can give us support in areas of our life that our partner may not be the best at. It's always a good idea to have more than one person in your life for emotional support. The weight of being the main emotional support for another person is far too heavy and is often the cause of failed monogamy.
Make Love a Choice, Not an Obligation
Love is, of course, a choice. After reflecting on past relationships, my partner and I both came to the understanding that we wanted our love to be an active, everyday choice and not a default feeling. Not every day is full of sunshine and butterflies in our stomachs. That's completely unrealistic. Yet, we do wake up and decide "Yes, I'm going to show up for our relationship today and I'm choosing to love you."
We both acknowledge that, one day, one or both of us might wake up and decide that we're no longer invested. If that day comes, we can trust that it's a choice not taken lightly.
We will probably never get engaged or married. We don't want any more children (my daughter from a previous relationship is enough for both of us). When we decided to ditch polyamory in favor of a more singularly committed relationship, we had a long talk about which milestones we would (and would not) celebrate.
The traditional milestones won't work for us since they don't hold much weight in our minds. We do celebrate anniversaries, going on trips with each other, meeting members of each others families, and milestones like sharing a toothbrush (we did this and, even though I still think it's kinda gross, we both acknowledged it as an act of intimacy that we didn't have previously).
Never Stop Dating (Each Other)
This is true no matter how you label your relationship. Dating each other is what keeps you close and your relationship vibrant. It's too easy, especially in monogamy, to fall into a routine and wake up one day and realize that you're just glorified roommates or best friends.
We have our routines, sure. We also surprise each other with flowers, take romantic weekend road trips, and date each other like we did in the beginning. It keeps the spark going and ensures that we never run out of things to talk about.
Be a Whole Person Without Your Partner
This should probably be number one. It's so important to be a whole, complete person that isn't defined by your relationship. In poly relationships, this can be a lot easier. You're spreading your time and attention over a multitude of people, which it makes staying connected to who you are feel a lot easier. Butu how many monogamous couples do you know who are practically clones of each other? They have the same hobbies, same favorite foods, and listen to all the same music. They take on each other's personality traits and facial expressions and, if separated, are at a complete loss in terms of what to do. They need each other to be complete.
My partner and I knew that we didn't want to go down that road. We make sure that we're nourishing our own emotional and spiritual growth and taking care of our identities outside of our relationship with each other. This helps us show up as whole people who help each other grow, instead of halves of people that must be together in order to feel complete.