In short—
The child, she wanted; this father, she did not.
She had money, capability, and a wealthy family background, and she had always adored children. She could provide her own child with the best, and a 'dad' who cheated and was full of lies naturally wasn't included in that best.
Keeping the child and getting rid of the father—very straightforward.
One could even say it was perfect.
At least she quite liked Lei Yongming's face, otherwise, she wouldn't have dated him. Once the child was born, her family would raise it well. As for the lack of fatherly love—what nonsense was that? There were plenty of children from single-parent families. Besides, having no dad was obviously better than having a dad like him and such grandparents.
"You, I—I'm telling you, if you dare, don't expect to have an easy time!"