I was seeing someone who was a self confessed previous player, told me all about his previous lies, but he wasn't like that now because of X,y z. So forewarned is forearmed and I was wary to watching behaviour. In this case it was consistently and daily deleting messages from a woman- he neve uses a passcode for his phone, but I gleaned the info just by looking over his shoulder. Also a change from having his phone up, to keeping it face down. One night, after being suspicioy for a bit, I thought ' fuck it, don't mess about, just ask about it'.
Well, I already knew he had history of lying to his main SO, while doing bits on side and would think nothing of it, and lie he did. Next day, he suddenly passed the phone to me while on a walk, that was his brother who Id never said 2 words to before, and was all, " come for a visit, we'll do xyz etc". I was a bit pissed off about that because I was in process of reconsidering the relationship, so to pick then to involve family, seemed out of order
But the based on what he told me of his past, he regularly cheated on a girlfriend, then got someone else pregnant, so, they got engaged while he lied. I suspect he was trying same method on me - it didn't work.
Some men, when they cheat and/or sense they are losing your allegiance, start to future-fake all the more, in an attempt to make you forget your suspicions. Keep your eyes open, is my advice.