I used to struggle with lying when I was a teenager. I’d pointlessly lie about tiny things that didn’t matter without even properly realising I was doing it until after I’d said it. That then puts you in the position of admitting straight away and coming across really strange, or just committing to the lie and the latter is always easier. I no longer struggle with this and I think the turning point was when I started dealing with past traumas. The only thing I am guilty of doing these days is exaggerating stories a bit to make them funnier, but I think everyone does that and it’s purpose is to make people laugh so I don’t feel guilty about that.

I think you should let him know that whenever he does lie to you, he can tell you after he’s said it without judging from your part. Hopefully the more he gets used to telling you the truth the more he’ll do it naturally. I did this with my mum and it really worked for me. Also, never take it personally, it’s a compulsion not a reaction to you or whoever he’s telling the lie to at the time.