His best mate is a cheating pos- red flag number 1

He lied to you about his location when there was absolutely no reason to. =red flag number 2

Blameshifting - red flag number 3

He deleted messages with his best mate - red flag number 4

Trickle truthing about their conversation- red flag number 5

Still seeing nothing wrong with being wingman to a cheating pos- red flag number 6

As you stated, he's never been CAUGHT lying, does not mean he hasn't been lying. I honestly think they went out to hook up and your fella has likely been cheating on you as well, birds of a feather and all that. There are far too many red flags and excuses in your post that scream trickle truth. Go through his phone and socials. I bet you find an army of red flags there, check all his contacts.