Could this mean he is cheating ?

[Allornothingatall]

I was round at my BFs and he opened his bedside drawer. I’m not keeping tabs on the lube or anything but we bought a full bottle and together we hadn’t used it yet, but it had very clearly gone down,Is this a sign he is cheating on me?

He's using it for his own anal pleasure.

HTH.

Maybe he likes a luxury wank?

Agree probably for wanking. I very much doubt this points to him cheating, unless you have other reasons to be suspicious

It could be but more likely a "sloppy wank".

Why would that be your first thought and not that he’s just wanking?