Considering Saul hasn’t shown much interest in women beyond Kim for the past few seasons, one can easily assume the will go through a break-up before he meets Walt and Jesse.
Also, let’s not forget about what happened elsewhere in the Breaking Bad episode where Saul brings up Lalo’s name.
In a moment that still doesn’t completely ring true to Bob Odenkirk, Saul comes out of his office building and says to himself that his assistant Francesca is “killing it with that booty.”
Fingers crossed that showrunner Peter Gould finds a way to keep Kim alive through the end of the final season so that she might be like Jesse and get her own solo movie one day.