If this was a one-time deal, you may have trouble breaking the lease for this reason alone. You are entitled to "quiet enjoyment" of the premises. But the landlord likely has reserved the right to inspect the property under reasonable circumstances. Whether or not this was reasonable is another matter.
You may want to review the Michigan Tenant Landlord booklet, which you can find, here: www.legislature.mi.gov/documents/publications/tenantlandlord.pdf
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I agree with Mr. Frederick. A one-time occurrence like the one you described is probably not enough to break the lease. If he continues acting in this manner (dropping by unannounced), or if he fails to keep the premises in reasonable repair and fit for its intended purpose, you are likely to have a better argument. I hope it works out for you. Kind regards, Akiva.
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Based on the facts given, you would not be able to break your lease. Your lease probably doesn't allow subleasing. Your best option is to discuss your desire to move out with your landlord in hopes that they would somehow agree to it (in writing of course).