All mine contain the line “Happily married, ethically non-monogamous”
I didn’t do that to start with (because I was feeling shitty about getting few enough matches anyway) but I always brought it up within the first few messages.
I always expected anger when I raised it but everyone was very nice and if they weren’t interested they were at least appreciative of the honesty.
I feel more comfortable being poly/non monogamous now and get that if someone is not 100% behind it enough to not be put off by that line then it’s never going to be ok.