Wardell died aged 37 just two days after winning the Scottish MTB XC Championships.
Archibald, a two-time Olympic gold medallist, tried to save Wardell after he had suffered a cardiac arrest but was unable to bring him back to life.
She posted on Twitter: "I think you've heard that Rab died yesterday morning. I still don't understand what's happened; if this is real; why he'd be taken now - so healthy and happy.
"He went into cardiac arrest while we were lying in bed. I tried and tried and the paramedics arrived within minutes, but his heart stopped and they couldn't bring him back. Mine stopped with it.
"I love him so much and need him here with me. I need him here so badly, but he's gone. I can't describe this pain.
"Thank you to those making tributes. I can't bear to talk about him in the past tense to say anything myself. You mean everything to me, Rab. I love you."
Wardell won the elite men's title at Kirroughtree Forest on Sunday, overcoming several punctures to win on the final lap.
He appeared on BBC Scotland's The Nine programme on Monday evening to talk about his victory but died the following morning.
Scottish Cycling said in a statement on Twitter on Tuesday night: "We are devastated to confirm the news that international mountain biker and former employee, Rab Wardell, has passed away today.
"We have very little information at this stage, but we send our love and support to his family, friends and all those in our community who knew him.
"We ask that you respect Rab's family's privacy at this incredibly sad time."