If Jason is really returning, it has to be for Liz.
Sam has Silas.
The show has spent a lot of time establishing Sam/Silas as a couple.

Of course, Jason/Sam will have to interact.
They are married and have a child.

Hopefully, Jason is for Liz and we see him convincing her it will be different this time.

Liz will be very hesitant regarding Jason.
She hates herself for the paternity test fiasco.
Frankly, Liz would never do something like that in the first place.

There is no need for Jason.
So, if he returns, it should be for Liz.