Giz, I don't really have any advice as far as your relationship goes, but I do have some advice about living arrangements if he's determined to do this (and you're determined to let him). If he gets an apartment, there will be a lease to sign, deposits to pay, utilities to pay, living essentials, etc. If he thinks all he needs is a few months, then getting an apartment could be a mistake. He could get locked into a 6 month or year long lease.
Something that might make more sense is to call around to some extended-stay hotels or just regular hotels in your area and get some pricing for a two month (or whatever) long stay. The price might seem steep at first, but make sure you factor in all the additional expenses you would incur if he got an apartment. It might make more sense financially, especially if its going to be short-term, to go with the hotel. He'd have all of his utilities included, cable, and even some housekeeping. If a few months isn't long enough for him to make a decision, you'll probably want to look into more permanent options anyway.