To see if they were related you'd need to check Ellen's parentage and work back.
I have two sisters who married two Smith gentlemen and after much digging I found there was no connection at all!
On the other hand I do have several instances of brothers marrying sisters etc and I also have a gt gt aunt Emily who married a John Evans (can't get much commoner than that!). Emily's niece, Alice, married a Frank Evans and I discovered Frank was John's son by his first marriage. It all got extremely cosy when I found John and his first wife and family, and then Emily, living at the same address for over 20 years - next door to Emily's brother (another) John, who was my gt grandfather!