Um..what?? YOU need to "learn to let it go"??
You're dday was less than a year ago. The closer a BS gets to dday...especially that first dday antiversary,the more stressed they become. So your anger is normal.
It takes 3-5 years to heal from this shit.
And with him still blaming YOU for his cheating *and* saying he has had it with you being upset about it and wants to D...it's no wonder you are angry.
It's great that the MC told him this all lies at his feet...but I think telling you that you need to let it go is crap advice.
M: June 2001
..that feeling you get in your stomach, when you heart's broken. It's like all the butterflies just died.