How do I add multiple clients to an Opportunity?

The best way to do this in RealOffice360 is to pick one member of the duo as your "Primary Contact", whether that be the wife, husband or whichever. Once you pick who that is, you can then add an Opportunity to that "Primary Contact" which it sounds like you have.

From here, we suggest adding the partner not as a standalone contact, but rather a Family Member of the "Primary Contact".