How would you handle this situation?

If your agreement is $580/month, point that out to him. You paid him $580 for Feb, and you'll be paying him $580 for March too. Obviously bi weekly doesn't come out to exactly twice/month, because there are more than 48 weeks in the year. Maybe you should have phrased biweekly a little differently, and said you'd pay him twice a month, totalling $580.

From what I read into this you two have a differing ideas on payments.

what you need to clarify with him is that you are indeed paying $580 a month. If he agrees to that then all you need to do is show him the payments for January showing him that they totaled $580. Then show him the payments for February showing they totaled $580. If he knows it's $580 a month then he will see that he was paid the monthly amount.

Now if he has the idea that you are on a bi-weekly tenancy then he is figuring you are paying him every two weeks regardless of the monthly amount. That's when you will have a problem because you both do not have the same agreement in your minds. This is where a written agreement helps.

Good Luck!

Generally rent is paid in advance. He would have to pay rent to landlord or pay his mortgage on first of month.

Don't see what huge deal is. You got 3 paychecks in February, so pay him the first half of March rent. Why is this extra cash? You made two payments in February, for February. You make two payments in March for March, right? Or is there something I don't understand?

Are you truly paying biweekly, or are you paying semimonthly?

Wikipedia: biweekly (every two weeks): fortnightly Twice every month; semimonthly.

I would sit down with a calendar and show him where you’ve paid. I’m guessing from what you said, you paid on Feb1, Feb 15, Feb 29. Maybe he needs a little refresher that in 75% of years, Feb, 29 would have been March 1.

I say just pay him 580.00 at the beginning of the month, even though it wasn't agreed upon. I just say that so you don't have to stress about him going crazy for rent.