Most Helpful Guy
Mail him his stuff and you will not get the closure you're wanting nor will you end on good terms. This is the real world of dating. So many women on here think they can remain friends and I laugh at all of them. Don't ever say or agree to "let's be friends" because it won't happen
Most Helpful Girl
If he doesn't want to talk, that should speak volumes to you on how much he cares (or the lack of caring for that matter). When someone is in a relationship with you, and they love you, and when they do something like cheat, they should be doing everything they can to make things right for you. They should want to save the relationship and make an effort.
If he's not wanting to talk, then that to me says that he doesn't care. Even if he's not a chatty guy, the thought of losing the woman he loves should be enough to make him want to step out of his comfort zone and talk to you about it.
As for his stuff, stuff it in a box and leave it out side his house. Text him to let him know it's there.
I went through a similar break up a few years ago. The guy I had been with and told me he wanted to have a life with me, I found out he was cheating. He never admitted to it, but I found out because he was trying to hook up with a friend of mine.
I couldn't trust him anymore and so I had to move on. It hurts like heck and you are really affected by it sometimes, but you know what, one day you will be okay.
It's totally normal to feel like crap and cry. It's okay if you have to talk to a friend or if you don't feel like you can date anyone else for a while.
Take some time for yourself to heal. Invest your time in friends and family who enrich your life. Take on some new hobbies to keep yourself busy and keep your mind off of what happened. Journal your feelings if it helps and over time you will start to feel better.