Do you mean Comprehensive Sickness Insurance (CSI) in the Netherlands? Usually, you should get an ehic from the NHS before going to the Netherlands if you had been resident in the UK previously.
Also, I thought if you are a worker in an EEA country, usually you - and your family members - are entitled to be covered by the state health insurance scheme of that country - if as a worker you are contributing towards the state health insurance scheme. Generally, if they are contributing towards state health insurance schemes workers do not require third-party CSI.
It is important to check the health care schemes in your specific country though.
For the Netherlands, the health care scheme is in fact run by private insurance companies.
Here is a link to the Dutch Govt website:
http://english.minvws.nl/en/themes/heal ... efault.asp
This is another website explaining it:
http://www.expatica.com/nl/health_fitne ... he-NL.html
For satisfying EU Directive law it is self-sufficient and their family members and student Qualified Persons that require CSI ( so they are not relying on the CSI provided by the host country and open to accusations of not being self-sufficient).
Or are you asking if you will need CSI if you returned to the UK with your spouse?
As Directive pointed out, if your job is "black" or "on the side" then they won't accept that as legally being a worker for the exercising of Treaty Rights.
Thus, as explained, you need to register as a worker. Or you can exercise Treaty Rights by registering as a jobseeker until you find a legally recognised employment- keep proof you registered as a jobseeker, of applications, interviews etc until you find another job or your current one becomes legitimate with regards to being recognised as a worker by the Govt.