Am I right in assuming he has freedom of movement when travelling with me?
If you are travelling to an EU member state that is not the state you are a citizen of, freedom of movement applies to him too.
Beneficiaries
- This Directive shall apply to all Union citizens who move to or reside in a Member State other than that of which they are a national, and to their family members as defined in point 2 of Article 2 who accompany or join them.
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Right of residence for up to three months
Union citizens shall have the right of residence on the territory of another Member State for a period of up to three months without any conditions or any formalities other than the requirement to hold a valid identity card or passport.
The provisions of paragraph 1 shall also apply to family members in possession of a valid passport who are not nationals of a Member State, accompanying or joining the Union citizen.
Directive 2004/58/EC
We live in the UK and have a home in Spain. We like to stay 2 months at a time, are we allowed to come and go whenever we want, for instance May-June (2 months), September-October (2 months), January-February(2 months) etc, without having to count the 90 days within 180 days?
If you are not a Spanish citizen, his Schengen clock doesn't run when travelling with you. Just make sure to carry proof of relationship.
As each stay doesn't exceed the maximum 90 days, does this mean he doesn't have to apply for a residence permit as we are not residents, only stay part-time?
You won't need to apply for a residence permit but make sure to understand the tax implications if you are in Spain for more than a 183 days in a given year.