Well u re not overreacting at all but as others have stated the real disrespectful act was having sex with another man regardless of the details. Of course you have to eliminate all symbols of their affair including changing your bedroom, her phone..., as they are all trigers that hinder the process of healing.
Also and as other have stated more feelings will come up as you walk this long painful road and that requires you to develop your coping mechanisms to avoid being stuck.
For me i found that success in my career and in being a better person and dad is a great push helping me get past this messs.
You will never forget these traumatizing events but will reach a point where they won't hurt you as a much, only a scar that rreminds you of a struggle that you overcame with your ability to survive and tthrive in life.
Bottom line is work on yourself and focus on things that give you satisfaction about who you are.
Again I say that for me and looking at the AP and his family, it gives me satisfaction that im doing better than him in my life and that he ll always look up to me and never achieve what i did in my life cause im better than this scumbag will ever be.
We re all here for you.