Becoming a partner alongside my secondary occupation

Hello,

I work 50% as an employee and I am self-employed in secondary occupation; I run creative workshops. I am not subject to VAT.

I have now been offered the chance to become a working partner in a cooperative. I would only be working for a few hours a month (4 to 8). I would also be running creative workshops there.

Does anyone know if the partnership will affect my secondary occupation in any other way?
I wouldn’t want to suddenly be taxed more heavily, or for my secondary occupation to suddenly be regarded as my main occupation or anything like that.

Thanks in advance for your help!