Trying to heal?

My boyfriend of nearly 4 years (March 6th woth be 4 years officially) was looking up and messaging multiple women on x and reddit for sex or to send pictures for 3 years i recently found out a month ago I gave him the decision to stop and I'll stay I did and later found out 3 weeks ago he sent an account to himself on *** he says its just cause he'll scroll on reels and sometimes it'll pop up but fully admitted (AFTER I caught him) to yes he sent it to himself.. am I stupid for trying to stay? We are in couples therapy and live together.. I've been cheated on in the past and I'm tired our therapist recommended I try to bond with people in my situation that had gotten past it and are with the spouse that cheated and see if life got better so I guess here I am? Thank you