Could this be a lesson that it's better to get the 90 day visa based on marriage before coming here? We often say, get the visa that best fits your intentions.
Sounds like you paid the fee for the marriage extension. You don't get multiple entries with that, you buy re-entry permits, 1 for 1000, multiple for 3800.
you don't need to notify your landlord. You can come and go as you please. You paid rent when you weren't there. It's what we all do, it's not special in any way but you might need to tell him you returned. He might need to file a new TM30 although I really don't understand why.