Side note - I had to read this twice:

I have a partner who is non-binary but AFAB, has had two kids, and is going through perimenopause. They have strong monthly cycles

At first I thought you were saying that all three of them - mom and kids - have strong cycles. That makes sense, since it's known that women living in close company can synchronize their cycles, but your later discussion makes that sound really weird.

After a few re-reads, I realize that it's a pronoun problem. Your use of the plural pronoun made your comments rather more difficult for me to read.