extrat non diagonal

hello
for examplei have this matrix
w2<-c(0.1,0.2,0.4,0.2,0.4,0.1)aa<-matrix(w1,nrow=3,ncol=3)aa
???? [,1] [,2] [,3]
[1,]? 0.4? 0.4? 0.4
[2,]? 0.1? 0.1? 0.1
[3,]? 0.2? 0.2? 0.2

if i use this code 
matrix(as.numeric(aa)[!as.numeric(aa) %in% diag(aa)],2,3)

i will obtaine this matrix[,1] [,2] [,3]
[1,]?? NA?? NA?? NA
[2,]?? NA?? NA?? NA

but me i want this matrix[,1] [,2] [,3]
[1,]? 0.1? 0.4? 0.4
[2,]? 0.2? 0.2? 0.1

thank you