[ig1]

Firstly you have a mess you need to clear up, have you bought out your other co-founders to ensure you own 100% of the company ? - you'll struggle to find investors if you've got zombie cofounders who may claim to the company, you need to get the paperwork sorted out now.

Next understand why investors want you to have cofounders.

It's not some arbitrary standard, you simply won't have the cash to be able to hire a top tier sales, marketing person, etc. so bringing that talent onboard as cofounders is how you should be solving that problem. Find the best people you possibly can who cover the areas that you're weakest in. Find people who've experienced growing a similar company, they'll be invaluable to you.