Although Liz left the Spider-Man comic book series after she, Peter and their classmates graduated college, she returned almost a decade later, and since then she’s been a recurring member in his supporting cast.
Liz and Peter never officially dated in the main Marvel continuity, and eventually she married Peter’s friend, Harry Osborn.
However, she eventually came around and developed feelings for him, but by that point he was already dating Betty Brant.
Although Liz Allan doesn’t rank as high as Mary Jane Watson and Gwen Stacy on the list of Spider-Man’s love interests, she did precede all of them.