Replace Portuguese with French and I'm you. I can't give you advice but only tell you a bit about my story.
We were worried my child wouldn't speak French and that if he picked up Korean first then I wouldn't be able to communicate with him. So I spoke French and wife spoke English, and he ended picking up French. Until a bit more than two, he would speak 90 percent French, which made life difficult for my wife, although he could understand English very well. (No daycare by the way.)
Then all of a sudden English started to surpass French. Finally slightly before the 3yo mark my wife started working on the Korean, and he's been going to daycare from around 3 and a half.
Now he's fluent in the three languages, although he speaks with accents, and he's not equally good in all three. I now speak equally in French or English, but I do make an effort to keep the French.
I think there's still a long way to go, but I'm thinking that he should be well settled with the three languages when he's around 6. It's a long run play, but very beneficial to the kids without a doubt.