After they broke up, they kept in contact and continued to have sex.
By late July 2020, Ashton said she wanted to move on and to pursue other relationships.
Wenzlick started making frequent unannounced visits to her home and sending "prolific text messages".
Ashton began seeing Buckeridge, from Rotorua, and stopped answering Wenzlick's messages.
On July 28 and 29 Wenzlick's messaging continued. He described himself as a "love struck psycho" and how he wanted to reunite with her and her children.
He also made threats about any other men that she might be seeing, writing "I'm going to set an example of what is going to happen to any man that touches the woman I want", and "if you f*** that dude I'm going to have to get rid of him too".
Another one ended with "I will eliminate anyone who gets in my way".
On the afternoon of July 29, Wenzlick, a farm worker, again went to her Cambridge house, but she gave him the fingers and pulled the curtains.
Undeterred, Wenzlick lurked outside the house for a number of hours, sometimes knocking on windows to get attention, and asking Ashton to go outside and talk to him.
Later, Ashton and the victim went to bed. Wenzlick began furiously texting Ashton again before sending one which read, "f*** you aye, I just spent two hours stalking Mark setting up to kill him and you're here cuddled up to this f*** head".
Wenzlick managed to get inside the house and when the victim got up to go to the bathroom Ashton felt someone hugging her from the other side of the bed.
She looked down to see Wenzlick next to her between the wall and her bed.
She ignored him, and when the victim returned, she rolled over to hug him and they went to sleep.
Shortly after 5am, Wenzlick sent a photo of himself holding a hammer in her kitchen and wrote, "Might have been on the floor next to you for half the night but next to you is where I want to be".
Soon after he texted: "See you today sometime please. You actually don't know what I've done to be with you. And what I am capable of ... I could have killed him several times over last night while you were sleeping and you wouldn't have even known until you woke up."
Wenzlick left but returned about 9am and found the pair still in bed.
He then struck Buckeridge with the hammer around the head at least five times, using "considerable force".
Ashton tried to intervene but was inadvertently struck.
The victim suffered a severe brain injury, several skull fractures, bruises and cuts.
He is now at a specialist facility where he is getting intensive occupational, speech, language and physical therapy.
In late September he was finally able to eat textured foods again but he had since been diagnosed with post traumatic stress and would now likely suffer from seizures, psychiatric abnormalities, cognitive decline, sleep and motor disturbances and social engagement issues.
Wenzlick pleaded guilty to charges of attempted murder and assault when he appeared in the High Court at Hamilton in December last year.
Wenzlick was convicted by Justice Graham Lang and remanded in custody for sentencing on February 16.
