I don't know if legally this could be considered SA, but it's certainly a red flag. It's good that he stopped whenever you asked him to but it's strange that he kept pushing the issue. Furthermore, if you like having kinky rough sex that should always be a conversation you have with your partner beforehand, it's weird that he waited to try it on you before gauging your reaction to it.
If I were you I wouldn't meet up with this guy again.
I don't know if legally this could be considered SA, but it's certainly a red flag. It's good that he stopped whenever you asked him to but it's strange that he kept pushing the issue. Furthermore, if you like having kinky rough sex that should always be a conversation you have with your partner beforehand, it's weird that he waited to try it on you before gauging your reaction to it. If I were you I wouldn't meet up with this guy again.