since you and your wife have been separated for a more than a year, she has the right to make her own choices, including having an abortion. As she’s not living with you and the two of you are separated, she can be with whoever she wants without needing your consent. Each person is entitled to their own decisions, especially when it comes to personal matters like relationships or health.
this does not count as cheating or infidelity as you said you both are separated.
and moreover abortion is a women’s right, she can get it without the consent of her husband.