Stathi Katsidis' death will forever remain a mystery to his fiancee Melissa Jackson.Jackson has revealed she had no reason to believe Katsidis may have turned to drugs in the week the champion rider was set to partner Shoot Out in Saturday's $3 million Cox Plate at Moonee Valley.Jackson opened her heart to listeners on Brisbane Radio TAB on Wednesday."Nothing was different," she said."He played tennis with (jockey) Brad Stewart in the morning and we met for lunch."I think he started thinking too

Stathi Katsidis' death will forever remain a mystery to his fiancee Melissa Jackson.

Jackson has revealed she had no reason to believe Katsidis may have turned to drugs in the week the champion rider was set to partner Shoot Out in Saturday's $3 million Cox Plate at Moonee Valley.

Jackson opened her heart to listeners on Brisbane Radio TAB on Wednesday.

"Nothing was different," she said.

"He played tennis with (jockey) Brad Stewart in the morning and we met for lunch.

"I think he started thinking too much and wanted to relax."

Jackson confirmed she had gone to bed after quarrelling with Katsidis on the night of his death.

"I don't know what happened and I never will," she said.

"Nothing dramatic happened where I saw any danger signs.

"He had a lot of pressure but I don't know. I'm lost for words."

Jackson believes Katsidis' death should be a warning to others who use alcohol excessively.

"He was drinking at home and I didn't want to fight with him so I went to bed," she said.

"Alcohol doesn't go well with a lot of people. I want to make people aware it can lead to disastrous things.

"Alcohol is not the answer."

Katsidis' manager Trevor Lansky refuses to prejudge any autopsy result which will determine the 31-year-old's cause of death.

Police have ruled out foul play or suicide.

Jackson said Katsidis sweated every day for up to three hours to be a jockey and in recent times just wanted to relax.

"He used to sweat for three hours a day and just wanted to relax. He did and he's in peace now," she said.

Jackson recalled the days when Katsidis was a battling jockey, struggling for rides and finding it tough financially.

"We used to lay in bed and watch heaps of movies," she said.

"We were really bored. We had nothing to do and had no money and couldn't go anywhere.

"He said one day we'll be so busy we won't be able to say hello some days.

"I'll cherish those moments for the rest of my life. I love him so much and I always will."

Jackson first met Katsidis at Rockhampton in central Queensland when she was 16.

"We were just friends," she said.

"I met him again when I was 20 and we dated for a little while but I was a little young.

"We met again when I was 25 when he was going through a tough time."

Jackson said Katsidis was a devoted family man and caring person who loved her son, Brooklyn.

"They were best friends. He (Brooklyn) made Stathi work harder because he felt he had something to work for," she said.

"My little son found him with me yesterday.

"We used to have family hugs every night before we went to bed.

"We'd all sit on the couch and have a cuddle and talk about the best part of the day.

"He'd become a real family man and father and so many things stood out. He was a shining star."

Jackson believes she was lucky to be Katsidis' partner.

"If Stathi taught me anything it's that no matter what happens in your life you have to regroup and keep going and do the right thing," she said.

"I know he still lives within me and I'm going to grow from this. I'll cherish those moments for the rest of my life.

"I was so lucky to be his partner."