This may not be particularly helpful for your current circumstances, but if you decide you can make it work with him coming over here and not working for a few months, this is what we did. We were doing this as cheap as possible since we had to survive on just my income.
I met my partner online in Nov 2013. In April 2014 he came over here on the 3 month visa waiver (he's American). Two months later we applied for a sponsored extended visitor visa which took us up to the end of September 2014. With that my partner wrote a letter about our relationship and how we wanted the extension so we could gather more evidence for the partnership visa, the tenancy agreement (which shows me as the lease holder and him as an occupant) and bank statement showing we had ~$1800 in the bank (it was pay day). At the start of September (don't leave it this late to apply for your visa :P) we applied for the partnership visa. With that we supplied:
-The same tenancy agreement as before.
-Bank statements from April-current, the account was a joint account from May onwards and showed our address
-We saved every single receipt we got from April-current, highlighted whose debit card was used to pay (both went to the joint account anyway) and noted what each of them was e.g. "We met up for lunch on my lunch break at work and got nachos and a soda." They were all in a ziplock bag and I have no idea if the immigration officer bothered to go through them all, but hey.
-Mail addressed to each of us. We didn't have any mail addressed to us jointly (aside from the bank statements, but those were just printed off from the bank rather than mailed). His mail was regarding his bloodwork results (he did the immigration medical here in NZ) and his police clearance from the states, as well as order confirmation emails we printed off from The Warehouse and Trade Me e.g "[Full name], your order has shipped. Details as below: [Our address]."
-Photos of us together. These were almost entirely selfies that I had posted to facebook, printed off showing the dates they were uploaded as well as the comments from friends, as well as the "[Her name] and [His name] are now in a relationship" post from Facebook and all the comments.
-A timeline of our relationship e.g Date we met, the date we went to stay with my family, when we opened the joint bank account etc.
-A letter from each of us regarding our relationship. They were very sappy and each ~3 pages long.
Living on one income for 6 months sucked, but it worked.