Moving to Germany but continuing to work with UK counselling clients

As Danyjr already wrote above, it is definitely POSSIBLE to legally work for foreign clients remotelyin Germany.

Your German wife can just move here, register and start work right away. You (non-EU spouse) have to get a Family Reunion Visa beforehand, and fulfill some more requirements after arrival, before you can work.

However, both of you would be self-employed, which involves an extra layer of complexity for business registration, social security like pension, unemployment and health insurance (you have no employer contributing to this!), accountancy (How to write legally correct bills to your non-EU clients?) and taxation (How to account for the fact that they do not have to pay German GST, but you do?). Get professional advice for there before you start, as doing things wrongly can cause a lot of hazzle!

Also: Make sure that you have no (tax or other) obligations to the UK authorities (something to be discussed on the UK forum, not here). Double taxation is more likely than the opposite, if things are done the wrong way!