Apologies if this is old news, but JT is rumoured to actually be quite the scumbag. Apparently, he cheated on Britney Spears and mistreated her a lot when they were together all those years ago. She got super upset and lonely, as you can imagine, and grew close with another guy as a result of it. In retaliation, Justin dumped her, wrote 'cry me a river' made no secret of the fact it was about her, slut-shamed her for all the press to see, and encouraged a massive slut-shaming dogpile on her. The subsequent years of tit she got from the press as a result of this played a large part in her eventual breakdown in 2007. He also supposedly cheats on Jessica Biel, or did as recently as a couple of years ago.
Again, sorry if this is already well known, I read it on a super pro-Britney twitter thread two or three years ago and fell down a bit of a rabbit hole. No smoke without fire, maybe?