If a man is kicked out of his home after his wife moves her boyfriend in and is then told he can't come get his things, what are his rights?

Go file a complain at your police station and have them accompany you to the house to retrieve your belongings.  Your wife is not entitled to keep your personal belongings.  If you can file for divorce do that, then all assets and personal items will be equitable distributed.  She can demand alimony, but that doesn't mean that she will get it, especially if she earns more than you.