We spend a lot of time in our pod considering how decisions within individual relationships, or as individuals, impact our partners, our metamours, and affect the larger grouping as a whole. This is largely selfish. That may sound kind of counter-intuitive, so bear with me. When my relationship sphere is stable and well-nourished, my life is more relaxed, and I am better fed by my partners. In taking care to consider the needs of others, as well as myself, I create the best conditions for my own health.
That said, there comes a point where the desire to put others before self becomes destructive. There is such a thing as too much generosity, and giving beyond the point of one's ability is a line to remain cognizant of.
When thinking about giving something that one values to another relationship/partner/metamour, consider for a moment: Are there are feelings of martyrdom attached to that choice? Is the offer being made as a preemptive strike to avoid being asked for something you don't want to give? Would it be difficult to say "no", were a partner to make the suggestion? Will it damage you, or your relationship with a partner to say "yes" to a request? If those answers aren't clear, don't put that into the pot, or let your partner/metamours know that this involves a, "Make it up to me." scenario.
Recently, there was a night slotted for a date with Russell at a time where the need was high for a shared conversation with Camille, between the two of them, and the three of us. It could have been pushed off, but that likely would have caused additional discomfort to all involved. At the same point, I wasn't really jazzed up about missing that date night, since it was following a trip they'd been on together, and I had a need for reconnection. In the end, I opted to offer up the date night to have that important conversation together, but also made clear requests for additional time and energy to be slotted into our relationship within the next few days to meet my need for reconnective time. Everyone got what they needed, even though it wasn't an easy balance to strike in the moment.
It's all too easy in poly to inadvertently become an emotional doormat to a partner's other relationships; to cease advocating for self, and just give until drained beyond renewal. Saying yes generally feels better to most of us than no, particularly when people we love are making those requests. Putting more on the table is lauded as a virtue, and asking for something "selfish" is often discouraged. Having needs can be seen as being needy, particularly in one's own mind, but when it comes down to it, the reality of human interactions boils down to, "What's in it for me?", and if that question has an unsatisfactory answer, the relationship isn't sustainable.