I absolutely love to travel, and so do both of my partners. We recently have tried two trips with the three of us together, which have gone really well, but one of my two partners says he would rather travel just the two of us. Each of us likes taking one trip a year, and one is all I can afford, so I can't go with each of them separately. So I'm left kind of torn.
This is a tricky situation! Kudos to your partner for speaking up clearly and honestly about his preferences, though, instead of doing something like sulking through the trip, trying to manipulate you into traveling without the other partner, or otherwise being less than healthy and helpful about this. And kudos to you for being someone who cultivates a safe relationship where he can communicate uncomfortable feelings without it turning into a fight. Great job, both of you!
It sounds like y’all have already taken two trips with the three of you, so that’s a lot of travel under everyone’s belt to be able to say that you’ve done it, and to know what works. There are going to be some compromises here, and it’s up to you three to figure out what is going to work. You could alternate yearly trips with each partner, and then on each partner’s “year off” from you, they can go with a friend, another partner, or solo. You could also switch to a three-year rotation, where you do pair, pair, then the three of you.
Or, you can try and get creative with your finances and your definition of ‘travel.’ Admittedly, there’s no replacement for a major trip to a new country or a special destination - but there’s a lot that you can replicate with less time and money invested. The fun of travel is getting away from daily life together, and having new experiences together - and you can do that more than once a year for sure! Taking shorter, more local trips is also awesome. If you don’t already, check out some of the online options for snagging cheap flights or hotels during the off-season (I’m a huge homebody, so I’m not well versed in these, but I know someone who recently went to Italy for less than $300 because he has a system for tracking cheap flights - hopefully some commenters or some online sleuthing can help you out.)
Talk to both of your partners about figuring this out going forward. It’s probably not possible for everyone to get everything they want, and it’s important to make space for some disappointment, but focus on what will work and where everyone overlaps.