Karen McKeown, from Bellshill, North Lanarkshire, is campaigning for changes to mental health provision after the death of her partner Luke Henderson.
She told the Public Petitions Committee she felt they were let down by the health service.
The father-of-two was suffering from hallucinations and “had become mentally unwell” during December 2017, Ms McKeown told MSPs, leaving her “desperately concerned for his safety”.
Despite repeated visits to accident and emergency departments, calls to GP surgeries and the NHS 24 helpline - a total of eight attempts for help - Ms McKeown said: “Every time we were turned away and abandoned.
“Every professional I spoke to, I made clear that Luke was planning on taking his own life. Time after time I pleaded for help.”
She found her partner dead on December 29.
Urging that “lessons must be learned”, she said: “Luke’s case is not unique - far from it. The same failures are happening up and down the country.
“We urgently need a mental health service that is fit for purpose.
“I need to look my children in the eye and tell them that their dad did not die in vain.”
A joint petition from Ms McKeown and Gillian Murray - whose uncle David Ramsay took his own life after being sent home by NHS Tayside despite three suicide attempts in four days - has gathered almost 900 signatures and its demands were heard by MSPs on the committee.
The pair are calling for round-the-clock crisis support and fatal accident investigations into suicides where the deceased has been in contact with the health service in the three months prior to their death.
“Most importantly, family concerns must be listened to and not dismissed,” Ms McKeown added.
She said a review into Mr Henderson’s death - which occurred just one day after he told NHS staff he was suicidal - found medics had not considered him to be mentally ill.
She said: “It didn’t investigate what actually went wrong; where was Luke actually failed? Was it the assessment tools? Was it the staff attitude? Where do the lessons need to be learned?
“I feel like the only way to gather that information is a fatal accident inquiry.
“If lessons could be learned, it could save lives.”
Labour shadow health secretary Monica Lennon, who has been supporting her constituent Ms McKeown and her campaign, said the two women behind the petition are “both so courageous”.
An emotional Ms Lennon added: “What Karen’s talking about today isn’t so much legislative change, partly it is about culture change and the attitudes.
“The fact we don’t have integrated health and care information, where there are gaps, people fall through those gaps.”
Conservative MSP Brian Whittle was also close to tears as he told how he once accompanied someone close to him to a GP after three suicide attempts.
Mr Whittle said: “It looked like he was leaving that surgery without getting any help whatsoever.
“As a last role of the dice I said to the GP that if this person does succeed in taking their own life, I will tell everyone that I’d been in that GP’s surgery and raised this with him.
“I’m not advocating that, but it was only in saying that the GP then agreed to take some positive action.
“I am absolutely convinced that if I hadn’t taken that action, that person wouldn’t be with me today.
“You shouldn’t have to go to those lengths to keep you loved ones safe.”
The committee agreed to take the petition forward, as well as writing to the Scottish Government, charities and mental health services for more information before considering their next steps.