The revelation came in a poignant and heartfelt message from Laura D'Arcy on her Facebook page.
In it, she says that an engagement ring was found during searches of the house while Ross was still missing and that she will wear it every day "knowing we would have had such a beautiful future."
Thirty-year-old Ross went missing on Sunday, March 31 and his body was discovered on Friday, April 5 in a wooded area near to Crichton Castle.
Miss D'Arcy spoke at a press conference earlier in the week in a bid to help bring Ross home. The couple have a six-month-old son called Lewis, who underwent extensive open heart surgery in January after being born with a serious defect. The search for Ross included police drones and two helicopters – including the search and rescue chopper from Prestwick - and many of Ross’s workmates at energy firm SSE are understood to have joined the search effort this week.Miss D'Arcy's emotional message said: "Goodnight my amazing man. You were always there for the kids and I, I just wish I had been there for you when you needed me the most, I wish you just spoke to me and I would have helped you through anything!
"You were such an amazing Daddy! I told you this so many times.
"I have no words right now and I feel so empty, my soulmate is gone and my heart has shattered.
"During a search of the house an engagement ring was found. You did say you were waiting for the right time to ask me to marry you but we focussed on lewis’ health first. You know I would have said YES! I wanted nothing more than to become your wife. I will wear this everyday knowing that we would have had such a beautiful future.
"I now face the future without you by my side but I promise you Ross I will do as best as I can and bring up lewis so you can look down on him and be proud.
"So many people cared and loved you.
"Night night my yoshi I love you and miss you with all of my heart. R.I.P until we meet again ❤️ xxx ❤️"