Calvin Harris Feel Disappointed When He know Taylor Swift Dating With Hiddleston

Calvin Harris suspected something was up with Taylor Swift for weeks before their breakup and his suspicions were confirmed Wednesday when pics surfaced of Taylor making out with Tom Hiddleston.

Our sources say Taylor and Calvin were in a "committed relationship," but he suspected something was up in early May ... a month before their breakup.

As we reported, at the time of the breakup Calvin posted there was still "a huge amount of love and respect." Hours after the photos surfaced Wednesday, Calvin deleted the tweet.

We're told, "He's pissed and feels betrayed by her."