"I miss you..." Such a simple phrase. It's something that I've said many times in relationships. In poly, we have even more opportunities to miss our partners, as our time is often split up. We are in different places, with other people, doing other activities, and aren't always with someone. We notice their absence, long for their presence.
What I noticed after a while was that "I miss you" also has other connotations. It can include elements of "I wish you were with me (and not with your other partner) right now.", "I'm lonely.", or, "I'm not getting enough time with you.". It has a tendency to ramp up the longing element, the angst of being apart, and puts pressure around time and/or energy scarcity on one's partners and metamours.
People have been taught that showing jealousy demonstrates true feeling for a partner. "Because I really love you, I feel jealous of your other partners." Sometimes it seems that missing someone, clearly and obviously, is an affirmation of emotional importance of a similar flavor. So, I thought that perhaps coping strategies learned to deprogram jealousy would come in handy working through the feeling of "missing" as well.
To that end, I conducted an experiment. For a month, I didn't use "I miss you.". Rather than focusing on how much I missed someone, I honed in on the anticipation of next seeing them. Instead of noticing how hard it was to not be able to share something with someone in the moment, I made a mental note (or a physical one) of what I wanted to talk about, and looked forward to having that be a contribution to our next contact. Rather than saying "I miss you.", I would say, "I am really looking forward to holding you again!", or, "It will be so amazing to connect with you next week!", or, "Can we get something on the calendar soon? I'm noticing a strong desire to spend time with you!" or, "I'm really anticipating our next date, love."
Perhaps it's just me, but ditching "I miss you..." made things feel easier. It was less uncomfortable, and more hopeful, for me to focus on the positives, to hone in on anticipation, to have a sense of looking forward, rather than getting bogged down in how much it sometimes does suck to be apart from someone you care for, regardless of the reason. It reduced the degree to which I sometimes felt envious, lonely, or not as prioritized as I wanted when my partner was with someone else, doing something else, or just plain unavailable to me when I had a wanting for them.
Try it. For a week, for a month, for however long you deem suitable; don't say, "I miss you." Target the positives, and keep the locus of your energy on what is coming up, rather than what is absent in a specific moment. The shift may pleasantly surprise you.