Employment is a work-for-hire agreement. Legally, your employer is paying for licenses, that does not grant you permission to use those licenses outside the scope of your employment. Everything you have (and create) at your office is your employer's not yours. That include software and/or software subscriptions. Unless there's some written agreement in place with the employer relinquishing rights to you, you have no permission to use anything outside the scope of your employment.
It's not much different than if you wanted to take the desk you have at the office home and use the desk for your own business. It's the employer's property and you can't rightfully use it for another business unless the employer explicitly tells you that you can take the desk.