How do i know what my boyfriend is feeling?

a few days ago i told him about things that i had done in the past... I'm not proud of them (they're sexual but it was before i met him) he says he's over it and he's not hurting from it but when i told him his eyes got red like he was going to cry.. i saw him tear up as well.. we were in public because i was so nervous i couldn't wait til we got back to my house (i wrote it in a note). We talked about it alone after we got back and i confirmed everything in the note he was worried about. he misread a few parts. i feel a lot better now that he knows but i still am not sure if he's hurting from it.. how do you know what a man is feeling or if he's hurt..?