Karleen and Mark Reece are going to use the winnings to convert their garage to create extra bedrooms.
The pair, from Stourport-on-Severn, Worcestershire, plan to give their three children some money before embarking on their fostering journey.
Teaching assistant Karleen, 42, said they had discussed it years ago but the circumstances had not been right.
“We’ve always wanted to become foster parents, however having enough space has always been an issue,” she added.
“Thanks to the win it’ll no longer be a problem. I’m so happy we can finally fulfil our dream.
“My three kids will be leaving home soon and I have too much love to give.”
‘His jaw dropped’
Mark, who plays the EuroMillions every Friday, bought a lucky dip for the 18 August draw at a Tesco Express in Kidderminster.
Normally, the couple check the results the same night but they were both busy and did not until Sunday.
“I showed it to my daughter, I said it was a practical joke,” said Karleen.
“We called out the winning numbers to each other and the amount from the website. As the realisation of what this meant hit us we sat there in disbelief; we were winners.”
Karleen said she was on the phone confirming the win with the National Lottery when her husband came home and she told him the news.
“His jaw dropped. He looked at me in disbelief so I put the phone on speaker and the lady confirmed… we’d won £100,770.14.”
Karleen and Mark, who is a site officer for Wyre Forest District Council’s recycling vehicles depot, plan to carry on working.
They will next apply for planning permission for their garage conversion and begin the fostering application process.
Karleen will also help her sister with her wedding, which had been due to take place in Rhodes but was abandoned due to the recent fires.
“It’s been a tough few weeks and so the win has given us some sunshine after being in a very dark place,” she added.