Travis Barker, Kourtney Kardashian. Dimitrios Kambouris/Getty Images for The Met Museum/Vogue Travis Barker is feeling grateful for the life he and wife Kourtney Kardashian have created together as she celebrates her 45th birthday. “Happy Birthday to my beautiful wife, soulmate and best friend forever,” the Blink-182 drummer, 48, wrote via Instagram on Thursday, April 18,…