Six-time Grammy Award winner JOHN LEGEND performs some of his soulful tracks in an emotional night with special guests India.Arie and Vaughn Anthony. Any couples on the verge of breaking up will definitely be ready to fight for their relationship after this trio of relationship experts drops some musical science on them. $39-$69. 8 p.m. Chastain Park Amphitheatre, 4469 Stella Drive. 404-817-8700. www.ticketmaster.com.