My Bf told me he is testing the waters ?

My bf and I are coming up on 3 years together (I’m 28 and he’s 26). We were living together for 2 months before he had to go back to his home country Brazil because his college visa had expired and he had to go back. He went back to Brazil in July and now is living again with his family and we’ve been doing long distance for the past 5 months. I picked him up from the airport yesterday because he is visiting me in LA and we are going on a trip to Hawaii together with my parents. I brought up what our relationship would look like moving forward and he told me he wants to take it slow and that he is “testing the waters”. I was so frustrated I don’t even know what that means and I was very upset because it’s already hard enough to do long distance. He has brought up me moving to Brazil while he’s working on getting a visa to come back to the US but that could take years to get. I’ve brought up how if I were to move to Brazil I would at least want to be engaged so that at least I feel like there is that commitment there since it’s a huge step. I just don’t know what to do and I’m really sad. Does anyone have advice ?