Travis Barker never thought he would fly in an airplane again after he survived a deadly 2008 crash — but thanks to now-fiancée Kourtney Kardashian, he's been able to see air travel in a different light.
For years, the crash — which killed four people, including Barker's assistant and security guard, and left him with third-degree burns on more than half his body — was "just too traumatic and painful" for the blink-182 drummer, 45, to ever consider flying again, a source tells PEOPLE.
"It wasn't until he started dating Kourtney that he was thinking about it in a more positive way. He felt like he was missing out by not flying," the source says. "He really wanted to take a trip to Europe with Kourtney."
For more on Kourtney Kardashian and Travis Barker's engagement news and other top stories, listen below to our daily podcast PEOPLE Every Day.
The insder adds, "They started out with shorter trips and he was doing well with them. He wants to make memories with Kourtney."
Barker, who popped the question to the Poosh founder, 42, on Sunday in Montecito, California, took his first plane ride in 13 years with Kardashian by his side, jetting off to Cabo, and later Italy and France, in August.
Travis Barker/Instagram Kourtney Kardashian and Travis Barker in Paris
The insider says the blink-182 musician is "relieved" to be okay with flying again, and though he'll "never love" it, he "feels great that he got to this point."
"He loves seeing Kourtney excited when they take trips. He focuses on this," the insider says. "Kourtney never put any pressure on him to fly. She was just there to support him. Travis gives Kourtney a lot of credit."
"It's still something very new to me, but having something that gives me the strength and hope to be able to overcome things that were so traumatic in my life, it just says a ton," he told the outlet. "She's definitely that for me. I'm invincible when I'm with her. It's just like I never dreamed, I never even considered flying again."
Jeff Kravitz/Getty Travis Barker and Kourtney Kardashian
The pair began dating earlier this year following years of friendship, and Barker proposed on Sunday on the beach at sunset, surrounded by candles and roses arranged in the shape of a heart.
A source previously told PEOPLE that the engagement was a "complete surprise" for the Keeping Up with the Kardashians alum, but that her family knew. Kris Jenner, Khloé Kardashian and Tristan Thompson were among those present for the proposal.
"Kourtney is of course ecstatic. She can't wait to marry Travis," the source said at the time. "She would also love to have a baby with him."
This will be the third marriage for Barker and the first for Kardashian, who confirmed the news on Instagram with a caption that simply said, "Forever."
Kourtney shares sons Mason, 11, and Reign, 6, and daughter Penelope, 9, with ex Scott Disick, 38, while Barker is dad to stepdaughter Atiana, 22, son Landon, 17, and daughter Alabama, 15, with ex Shanna Moakler, 46.