Hi again
I haven't found them on the 1861 but, you know me Monica, I looked at the marriage cert  
 
 
29 January 1858 at 21 Golden Square - Church of Scotland forms
Alex Fyfe, 59, Mason, widower, 37 St Andrews St, Aberdeen and
Amelia Mackie, 44, dressmaker,  spinster, 31 Chapel Lane, Aberdeen. Parents - William Mackie, farmer, deceased and Jane, maiden surname 
CruikshankSeems to tie in with your 1841 find, Monica, and, as she would have been 25-29 then , it  fits with her age  

So where were they on the 1861 - did Alexander die, did they emigrate  

Gadget