Bf said he sees me like a sister?!

So the other night my bf and I were having an argument. The argument wasn’t nothing to serious. So anyways when talking about our fight he was telling me how much I mean to him he said “I see u like a sister. Wait I know that sounds weird but I see u as someone I look up to and care deeply for. U been with me through the hardest time in my life and I’m going to be forever thankful for that. I’m glade god he put u in my life. Your amazing.” and when he said this I kinda got a bit confused and thought to myself “does he not see me as a gf?” But I didn’t say anything at the time. Today I brought it up and said “hey remember the other night when u said u see me as a sister? What do u mean by that? Like do u not see me as a gf?” And he said “yes! Of course I do. I see u more than that I see u as my wife. Well my future wife of course. Idk the sister thing was kinda weird but idk that was the only way I can describe my love for u”

Idk ladies I’m still a bit confused by this. We been together for 3+years and we been through ALOT during our time together. A lot of hardships in our life’s and a lot of growing in our relationship. Idk when he said he saw me like a sister I kinda got thrown off. What do U think he means by this?