But nothing prepared him for her devastating response - that she had contracted the HIV virus and concealed the truth from him.
"When I saw she was upset, I went through every possible thing I could think of," recalls Chris, of Canonmills, Edinburgh. "Then, for some reason, I jokingly asked, 'What, do you have Aids or something?'
"When she told me she did, I just sat there. I don't think I moved for three days. I can't remember what I said to her - maybe I shouted at her, maybe I swore at her but I don't know. I was in so much shock and I actually still can't remember much of that night."
Although Marie had hidden the truth from Chris and paid little heed to the consequences of having unprotected sex with him, she had told her entire family she was infected with HIV. For Chris, that made it even harder to deal with.
"That night, Marie's whole family came down to visit us and I found out they already knew," says Chris.
"I had gone to school with her brother, so I couldn't believe even he didn't think to make her tell me."
The couple had been in a relationship for two years and, as soon as he could, Chris went to the hospital to be tested.
And although the chances of a woman passing HIV to a man are less than the likelihood of a man infecting a woman, the test results confirmed his worst fears.
"I wasn't too shocked as I knew I had it - I'd prepared myself for the result being positive," he shrugs. "It still wasn't good to hear those words but I hadn't held out much hope."
The 40-year-old customer service advisor immediately ended his relationship with Marie, her deceit and callousness too overwhelming for him to accept.
"I just couldn't come to terms with how she could have done that to another person," he says. "I don't know how long she had it and how she got it - although her ex-boyfriend was a drug dealer - but she died a year and a half later.
"From the moment she told me I had nothing to do with her and never asked her why."
After his diagnosis in 1998, the next year was a blur. Chris hit rock bottom and began to suffer from depression.
Then, just when things couldn't have been worse, he was diagnosed with cancer and had to endure 15 weeks of chemotherapy and radiotherapy before being given the all-clear.
"It took the best part of a year to get back on track and, it wasn't that I was scared of dying, it's that I was scared of living a life with HIV and not knowing what lay ahead," says Chris.
"I was scared about how it would affect my future - partners, my health, football, work, everything.
"Telling my mum was awful. She's 80 so it was a lot for her to take and she was devastated, but my brothers were great about it.
"My friends were all shocked and said things like, 'but you're not a junkie' and 'you don't sleep around'.
"I was just a normal Joe. I had a girlfriend, I had a job, I went out with my mates, I played football. I didn't do drugs, I wasn't promiscuous, yet it happened to me."
Remarkably, Chris now manages to lead a relatively normal life, although he has to check in frequently with medics to make sure his body is continuing to cope. He's on a combination therapy, taking six pills a day, and he has a blood test every three months.
And nine years after Marie's devastating admission, and thanks to his new girlfriend Sarah Swanson, whom Chris describes as the love of his life, his fighting spirit has returned and he says he's never been happier.
Due to their new-found happiness, Chris and Sarah agreed to tell their story to Stephen Fry and a BBC film crew for a new two-part documentary aimed at renewing awareness of HIV and Aids.
"Day to day, the HIV doesn't affect me at all," beams Chris. "You can get small things like eye infections which are symptomatic of HIV but I don't feel any different at all."
Chris met Sarah, a 31-year-old customer services advisor, last October, when she joined his department at Scottish Gas.
"Chris was my sales coach at the time," explains Sarah. "I really liked him instantly - he was just so positive and fun."
They had their first date in January and they both knew they had found something special although, at that stage, Sarah had no idea that Chris was HIV positive.
It was when Sarah was talking about another colleague who had gone on to develop Aids that Chris said he had an admission to make.
As Sarah goes on to explain how she felt, her eyes well up with sadness.
"I was gutted," she says simply. "Gutted for him, gutted for me, gutted for his mum.
"I really liked him and hadn't felt like that about anyone - even though I hadn't even held his hand or anything.
"I just thought he was the guy for me. . ."
And it was just as difficult for Chris too. He explains: "I told her at the start so she could leave if she wanted to. I just had to lay my cards down on the table and be honest. I was so worried Sarah would do a runner but even then I knew she was different."
While Sarah remained in the pub that night - talking but avoiding the subject of HIV - the following day, Sarah grasped the enormity of Chris' admission and she wept.
Despite the shock, the two remained close, spending time together watching films and chatting, and Sarah began researching HIV and its implications.
"It was a slow burner," laughs Sarah. And Chris adds: "The fireworks were there, they just hadn't been lit - yet."
Sarah continues: "The first time we slept together it was scary but I'd armed myself with enough facts before we did anything, so I knew I'd be fine."
Six months to the day after their first date, Sarah moved in with Chris and, thankfully, her parents were supportive of their relationship, giving her their blessing and becoming experts in the virus themselves. And while the couple are unlikely to have children, they haven't ruled out the possibility and are researching ways they could have kids safely.
"I'd never really thought like that before," says Chris. "Maybe I wasn't with the right person."
Sarah agrees. "I was the same - I never wanted kids. But now I realise I just hadn't met the right person."
So has Chris' outlook on life changed? "Not really," he says. "I appreciate everything more and I don't get worried about the small things. I do consider myself as normal. The drugs are so advanced now that I expect to live a normal life and I don't expect to be dead before anyone else. I don't know the life expectancy of someone with HIV and I don't want to know."
Chris now plans to devote much of his time to raising awareness of HIV - something he feels passionate about.
He says: "I, like everyone else, thought HIV would never enter my life. I naively thought it was just gay men, drug addicts or people from Africa that got the virus.
"So when I saw the BBC advert in the hospital in March, I contacted them and within a couple of days Stephen Fry was in the flat doing the interview. Showing that anyone can get it was important to me."
• HIV and Me will be screened on BBC2 at 9pm tomorrow.
HIV is the virus that causes Aids (Acquired Immune Deficiency Syndrome) - a collection of illnesses and conditions, such as cancer or pneumonia, which occur because the body's immune system has been damaged.
Since the early 1980s when little was known about Aids, 25 million people have died and more than 40 million now live with the virus globally.
Health Protection Scotland figures show that more than 80,000 people in the UK are living with HIV and young straight people are one of the fastest growing groups of new diagnoses.
The latest figures also show there were ten new cases of HIV recorded in the Lothians between April and June this year. Across the country, there were 73 new cases, with the majority among men who had sex with other men. A total of 1988 cases have been recorded in the Lothians.