Aarolina Rutkowska, 35 and of Cross Farm Road in the Peasley Cross area of St Helens, was found not guilty of murder after his trial at Liverpool Crown Court.
Mireslaw Kowalczuk, 29, was fatally stabbed in the chest at a house on Cross Farm Road on 27 December.
He died in the ambulance on his way to hospital.
A woman has been cleared of murdering her partner who was found with stab injuries.