It sounds suspicious with his changing story. You would notice money issues or a lack of money, nose issues (things like nosebleed or a dripping nose), staying up late or all night, not eating/lack of appetite etc if he was doing it a lot.
One thing I have learnt is they are very good at lying and very good at manipulating. He will make you believe the sky is green and the grass is blue to hide his habit. Let it go and keep your eye on his behaviour etc.
My ‘husband’ swore on his dads life that he hadn’t taken cocaine for four years when I asked him. He had so many symptoms. I tell ya swearing on his dads life. He thought that by doing this I would wholeheartedly believe him.
Cocaine turned him into a manipulative liar. My cousin was horrified when I told him, all he could say was ‘he’s lying’