Kelce, 34, spent much of the summer working while travelling around Europe to follow Swift, also 34, and her Eras Tour with family and friends. However, before shifting his focus back to football, Kelce savored every moment he had with the 14-time Grammy winner.

A source told PEOPLE how hard it was for Travis to leave Swift in Europe while he headed back Stateside.

‘Travis’ last few concerts were bittersweet,’ the insider shares of Kelce’s trip to Germany.

‘They knew their time together like this was coming to an end and he made sure to spend every minute he could with Taylor,’ the insider adds.

Travis Kelce 'spent every minute he could' with Taylor Swift before heading to preseason

Travis Kelce ‘spent every minute he could’ with Taylor Swift before heading to preseason

While their demanding schedules often force Swift and Kelce to be in different cities, the pair takes any opportunity they can to be with each other between concerts and games. As seen with Swift’s globetrotting effort to be at the Super Bowl in February, they are willing to fight zip codes and time zones for each other.

‘It’s definitely tough to be apart but they do everything they can to make it work and show up for each other,’ the source shares. ‘They’re so in love and very, very happy together. All their friends and family can see it.’

Nonetheless, Kelce – who also spent his offseason shooting Are You Smarter Than a Celebrity and Ryan Murphy’s upcoming series Grotesquerie – is ‘back in football mode,’ says another insider.

Kelce spent much of the summer working and following Swift's Eras Tour in Europe

Kelce spent much of the summer working and following Swift’s Eras Tour in Europe

A source told PEOPLE that Kelce and Swift are 'so in love' despite being away a lot

A source told PEOPLE that Kelce and Swift are ‘so in love’ despite being away a lot

Kelce and the Chiefs will open their title defense on September 5 against the Baltimore Ravens

Kelce and the Chiefs will open their title defense on September 5 against the Baltimore Ravens

‘His team and the Chiefs remain a top priority,’ the source added as they gear up for a threepeat.

The three-time Super Bowl-winning tight end arrived to training camp on July 21 and sported the return of his ‘Killa stache’ look. The Chiefs Instagram highlighted Kelce’s mustache look with a post captioned ‘KILLA STACHE IS BACK.’

The defending NFL champions will hold open practices at Missouri Western State University in Saint Joseph before their first preseason game against the Jacksonville Jaguars on August 15. Their title defense will begin on September 5 against the Baltimore Ravens.

On the other hand, Swift will perform in Hamburg and Munich this week before taking the Eras Tour to Poland. The record-breaking tour will return Stateside in October.