Okay, the confusion begins, is there more than one Jason?

Is Liz being cautious because she doesn't want heart broken again?
Or, does she realize he isn't Jason?

Jason being the love of Liz's life could be an excuse and/or reason she has returned to past loves and why the results never change.
Jason remaining and returning to the loves and life he knows can be the excuse/reason he never fought hard for a relationship with Liz.
We have not heard Liz is the love of Jason's life.
However, hopefully, with Jason returning we see his POV and he works for Liz and the life he has wanted for a long time.