In order to secure that position, he really spared no effort, coming up with all sorts of underhanded tricks.
And the reason he changed his mind, using the virus on her.
First: Ansel was protected, so it couldn't be used on him.
Second: He altered the original plan. This experiment was supposed to start years ago, aimed at dealing with Ansel. But plans can't keep up with changes, her and Ruan Tianling's appearance disrupted his plan.
His status faced greater threats, just threatening Ansel was no longer effective. He wanted to have a child of his own, then that child would have absolute inheritance rights.
But her mother would simply never give birth to his child, so to make her mother bear his child, he would find ways to threaten her.
That's why he decided to use the virus on her, she would need to find a matching bone marrow to survive, then a child of him and her mother might very well match her bone marrow.
