Why Does Someone Text Just Enough to Keep You Around?
Nothing holds attention like a reward you cannot predict, and people work this out without ever being taught it. The drip continues because of: 1) intermittent reinforcement, since an unpredictable schedule is the single most habit forming pattern there is, which is why slot machines exist 2) option value, because you are being held as a live option rather than actually chosen 3) the sunk cost of hope, since the longer you wait the more the waiting needs to have meant something. Being kept is not being wanted. Work out which one you are in.
The pattern
Unpredictable beats consistent for attention
You are an option, not a choice
Waiting makes leaving harder
Ask for a plan, not a reply
How the contact runs
Ask for a specific day and see whether the pattern survives a calendar.