Are you saying on every record, as you flip thru them one at a time, they only show the first related record? Or are all the records only showing one (the same) record in the portal?
Can you post a sample file? If not, can you post screenshots of the edit relationship dialog, and the layout in layout mode.
If you enter layout mode and click on the bottom part of the portal (To avoid selecting one of the fields) and drag it a few pixels, do the fields in the portal row move with the portal?
If not, the portal does not properly "own" the fields in the portal row. You can remove the portal and fields and start over or you can drag the fields away from the portal row, release the mouse button and then drag them back, being careful not to release the mouse button until the borders of the field are fully inside the borders of the portal row.