If you've been filing a SCH C all these years with you as the only owner of the business, then your wife doesn't have anything from the business income applied to *her* social security account. Only you do. Unless of course, you've been paying your wife as a W-2 employee and reporting that on your SCH C. THat would be the simplest thing to do from here on out.
THe other option is to close your sole-proprietorship/single member LLC business and open a new partnership (which requires a new EIN) with both of you as partners. That's a bit more involved though. If you wish to pursue the partnership path (which I don't recommend this late in the game) just let us know and we'll give you the details on what all is involved. (For that though, it would probably be best to seek the services of a CPA or tax attorney in your local jurisdiction - especially if your state taxes your income.)
