Answer: Regarding the security deposit, the landlord-tenant statutes do not directly provide direction. Since we don't know who actually "paid" the deposit and whether it was from their combined marital funds, I think this question should be asked, assuming you have the current address for both former spouses. If they both claim 100% of the deposit, you can issue a joint check and let them fight it out. Alternatively, you can issue two checks each for 50%, and let them deal with each other if one feels he/she go shorted. In short, it's not up to you to make a decision of one over the other regarding who gets the refunded deposit. But before playing Solomon, you should ask each of them for a jointly signed written instruction regarding disposition of the deposit. If they give you one, fine. If they can't agree, then you can refund it jointly or spit it 50/50. I prefer the first approach,
Remember that under ORS 90.300(15) and (16) you have a 31-day period to provide the ex-husband an accounting regarding the disposition of the funds - e.g. will there be any holdbacks? I would copy the ex-wife, since she may claim ownership to some or all of the unused deposit, even though she left early. If you fail to provide the accounting with any refund, within 31 days, you could be held liable for twice the deposit. Lastly, you should review ORS 90.300(16) closely regarding when the 31-day period commence.