The couple split up last summer after nine years of relationship, but the 33-year-old star wanted to celebrate his ex-partner's birthday together.
"Kourtney and I have spent every birthday together, between mine and hers, for the past 10 years, and her birthday's coming up. Do I just say, like, screw it and just fly to Iceland and surprise her?
"Let's say if, in a year from now or 10 years from now, we work things out - I would've hated to have missed a birthday," he said to Kris Jenner.
"The thing that I hear her say is that she just wants you to be a good person and a great dad and to do it first for yourself and then for your kids and then for her," she said.