The couple were attempting to turn a wine bottle into a vase as part of a viral trend.
However, Pritchard said it all went “horribly wrong” when Quinnen caught alight.
Quinnen, also a dancer, previously told her Instagram followers she was left needing “continuous hospital treatment” over the last seven weeks following the incident.
On Tuesday Pritchard told ITV’s This Morning: “I think what’s really scary is her clothes caught alight, her hair caught alight and it all happened so fast, yet felt like a lifetime scenario.”
Pritchard added: “As soon as the fire on her body, her hair, obviously her skin was out, we covered her in damp towels, we called 999, we did everything that we thought was the right thing to do and to get her to A&E as soon as possible.”
The dancer said Quinnen has had a skin graft, adding: “Moving forward with her recovery, the doctors have talked to us but they don’t know.
“They call her super Abbie because her skin is doing amazing.”
Describing the night she went into hospital, Pritchard added: “I remember the night so vividly, I sat outside the hospital all night knowing that she was not even going to come out.”
He was not allowed inside to visit her because of coronavirus restrictions.
Pritchard added: “You want to hug people in these scenarios and all we could do is be that lifeline on the phone, being in contact with her.”
He also thanked people for the “love and support” they have received, adding it keeps him and Quinnen “positive”.
Pritchard’s brother Curtis, who appeared on Love Island, also appeared on This Morning and urged people to be careful when attempting stunts and to “take safety measures”.