Actually, I think this opens up a good conversation for communication in relationships – partners may feel threatened/ashamed/embarrassed/scared of sex toys for whatever reason but communicating those feelings as to the WHY could help break down that stigma.
Anyway, I’m mostly a no. No, I don’t think using a sex toy counts as cheating – however, I think if that use is being used at the expense of a partners pleasure/intimacy/attention etc, then it can become an issue.
I had a partner who would masturbate secretly, a LOT, and neglect my needs – which definitely caused a lot of issues and we ultimately ended up breaking up. Not the same thing entirely, but that’s where I stand on the issue.