Wow! Radcliff this is amazing! I was thinking that they hadn't married at all. Thank you so much!

I wonder why they went all that way?
In 1841 there was a Jane Anderson in Morpeth with a family who I have mentioned on another post. This family, I suspect, is the one who were tried for the Matfen murder in 1856 along with my Great x 2 Grandparents James and Elizabeth Conroy. All were acquitted.
This 1841 family of Isabella, Jane, Eleanor/Ellen and Michael (Anderson's alias Allen) were all recorded as having been born in Morpeth. However, with the exception of Ellen/Eleanor there does not appear to be any records. I am sure I once read in a newspaper article of that time that this family were from the Scottish borders. I suspect that Jane who married Jacob was connected with this family in some way. Perhaps she may have been a cousin or a niece. The Andersons/Allen family who were tried at Newcastle with my ancestors do not appear in the 1851 census. I wonder if this family may have a Lamberton connection?
I forgot to mention that the first person you mentioned - Jacob Millar Anderson - was, I believe, Jane's cousin, the nephew of her Father Alexander. The Jacob she married was the son of Jacob and Ann Miller sometimes spelled Millar. Jacob, Ann and family also lived in Morpeth with son Jacob in 1851. By 1855 Jacob and Jane were back in Morpeth for the baptism of their first child, Isabella at St Robert, RC. Isabella later went on to marry the brother (Thomas Conroy) of my Great Grandfather. Jacob appears to have been an intermittent catholic, I might add, so I would not be surprised if they married in an Anglican Church.
A Jane Anderson was named as the Godmother of my Great Grandfather's brother James at his baptism in early 1853 at the St Francis Xavier R C Church near Waterloo Cottages where the murder of Dorothy Bewick took place.
I have checked on-line for Lamberton and it seems to be in Berwickshire. I wonder if the marriage record may be at the Berwick record office?