Constantine IX Monomachhos was a "fill out". As was the emperors before him (the ex lovers? relatives of Zoe that were murdered or disposed of.)
Constantines background and family connections, with among other the armenians, were a potential threat to the present real rulers of Byzans.
As I see it, it was important not to have unwanted pretenders stepping in to the role as emperor.
When Konstantin VIII died, Romanos Argyros/Argyropoulus had conveniantly been married to Zoe. He became Romanos III.
Romanos III was disposed of and Zoe married her lover Michael of humble background. Michael IV is probably disposed of, he ends in a monastry.
Michael V Kalafates enters as he had been adopted by Zoe. He sends her in exile in a monastry. On the protests of the pople of Constantinople Zoe is reinstated and Michael V and his uncle were blinded and sent to monastry.
As a solution Constantin Monomachos (a relation) is taken back from the exile where Michael had put him. He became Constantine IX Monomachhos. He had conditions and one of the conditions was that Maria Skleraina would be part of the imperial family. She was declared "Sebaste" aprox. 'under-empress'.
(Constantines mysterious disease may arouse suspicions.
Leon Tornikos, a relative of Constantine and Maria with armenian relations made an uproar that wasquenched.
When Constantine died, Theodora was empress. To fill the gap after her Michael VI Stratiotikos was adopted and became emperor. He was later disposed of and sent to monastry.
Negotiations with the rulers of Constantinople made the powerful Isaak Komemnos became emperor.