Gift tax is on the payor of the gift. The recipient pays zilch
Yes you don't have a tax issue till your relative gives 5 million, but he will still have to file a form for that every year. It can be done easier, you relative can gift you 14k, and your wife 14K, with no gift tax ramifications, (if your relative has a spouse then they can double it ). This is per year. So if you relative has a spouse, they can give you 56K for 2017 and another 56K for 2018, and this wont require any forms.