By 'developing a relationship' it means the Card Action. So yes, it applies for advancements to L3 as well - you can safely ignore the requirements.Great. Thank you Vangeli! This came up on round #2 with the "Family Oriented" life goal in game and bootstrapped me in raising a family on round #3.
As for the 'ensure' clause, yes again. You may either start a relationship or advance one you already have to L2.