Complex sentence: In 1999, MacLachlan met and began a relationship with publicist Desiree Gruber, who runs her own public relations agency, and would become an executive producer of "Project Runway" in 2004.
Split into simpler sentences: In 1999, MacLachlan met and began a relationship with publicist Desiree Gruber, who runs her own public relations agency. Gruber would become an executive producer of "Project Runway" in 2004.