A happy new year to you and yours my friend.
Technically there's no restrictions either during FLR period of 5 years or for subsequent ILR application.
Just for your info, the only residence restrictions come at the time of application for Naturalisation. For a spouse this would be a countback of 3 years.
Basically it's better to limit any absence from UK to 90 days each year of the final 3 years before applying for Citizenship.![]()