BMI is pseudoscience BS laced with racism and fat phobia. Fat shaming people and pressuring them to maintain a certain BMI, according to the science, leads to more harm than simply being fat.
Fuck that tool — you, and any kids you may have had together, dodged a bullet. Aubrey Gordon wrote a stellar book and has a podcast on the subject. https://www.amazon.com/What-Dont-Talk-About-When/dp/0807041300
I always see people say “we’re not fatphobic, we’re worried about your health, etc”, but those people rarely consider the research that shows far-stigma is terrible for your health as well.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866597/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6092785/
https://blogs.scientificamerican.com/observations/fat-is-not-the-problem-fat-stigma-is/
https://www.amazon.com/What-Dont-Talk-About-When/dp/0807041300