think about this for a second: your competitor is asking to copy your work.
If I were you, I wouldn't assume good intentions especially considering you are just a start up and in a race for marketshare.
If it were up to me, I would set a date a year or two in the future and then open source it then, but only AFTER you have a large enough lead against your competitors in the market.
There is no reason that I can see to open source the secret sauce of your entire product.
