No, they are not a sport power couple (well as far as we know)
Both were actually voted Male and Female Athletes of the Year by the International Sports Press Association (AIPS)
Bolt received a total of 804 votes (27.74%) after winning the 100m, 200m and 4x100m at the IAAF World Championships Beijing 2015, to finish in front of tennis player Novak Djokovic and footballer Lionel Messi. Bolt previously triumphed in this category in in 2008, 2009, 2012 and 2013, the other years in which he similarly won three gold medals at Olympics and World Championships
Serena on the other hand had Ethiopia’s world 1500m champion and record-holder Genzebe Dibaba and world 200m champion Dafne Schippers as competition. Serena has won this award both in 2012 and 2013 and has also won the Sports Illustrated Sport Person of the Year award for 2015.