EEA extended family refusal

Hi
im new here and my navigation through the forum topics is the best so my apologies if this topic has been raised..
i just had my application for an eea extended family residence permit for my partner and father of my daughter refused because we dont have insufficient evidence to prove for a durable relationship
weve been together for the past three and half years and due to the nature og my job(live in nanny we weren't staying together .. we moved in together right from the onset of finding out i was pregnant and my daughter is currently one and half years old.. most of our documents from tenancy to council were in my name initially cos we werent sure how to go about those with my partner and we had other issues like preparation for baby birth..
we will like to make a fresh application but my question .. how do i prove weve been in a durable relationship all these time without waiting to have the time we changed documents to both of our names to age to two years ...