"We're facing my eldest son becoming a stranger to me in the eyes of the law when he turns 18," says Paula Fagan.
A mother in a same-sex relationship, she and her partner Denise "planned our family together and were lucky enough to have our gorgeous boys, who are the centre of our world".
But Ms Fagan, CEO of LGBT Ireland, said that Article 41.3.1 of the Constitution, which protects the rights of the family and marriage "against attack", did not recognise hers.
Thousands of other Irish families' rights remain unprotected in a changing Ireland, she warned the Citizens' Assembly.
"Only one of us is legally recognised as a parent," said Ms Fagan, from Drogheda.
Each time the couple renews passports for their sons aged 10 and 13 they must sign a legal affidavit, stating "we're a lone parent, when we've been living together 15 years, raising our boys since they were born".
The couple can both avail of guardianship rights for the children's medical care but this entitlement "runs out at 18". Ms Fagan said the Constitution "needs to recognise, protect and uphold what matters in a family". But currently it's "a barrier to recognising our family. Marriage equality didn't fix this".
The assembly is debating gender equality, exploring the status of family and women within the Constitution.
Single mother Adele O'Connor and separated father Dave Saunders, from Tallaght, Dublin, also gave their personal testimonies on how the Constitution affected their lives.
Ms O'Connor said she was "disappointed in the status of the Constitution" which details family as being based upon marriage.
Mr Saunders, CEO of the From Lads to Dads focus group, said he had moved out of his family home 15 years ago after a relationship breakdown. While he had maintained an understanding co-parenting arrangement, he felt the Constitution had not recognised his or any other separated fathers' rights.
Leaving a home filled with the sight and sound of children playing had been "like a death" to him personally.
"You have no one to advise you to look after your mental health," he added. "As a man it's not being able to put your hands up" to describe mental strain due to separation.
The shaping of the nuclear family by the Constitution had only helped perpetuate stereotypes of "deadbeat dads", he said. But for most fathers "nothing could be further from the truth... we need advice on how fathers support children. Men want to be good dads, we just need help sometimes".
The assembly heard that last year about 38pc of births (6,046) occurred outside marriage. The assembly will again discuss gender equality at the Grand Hotel, Malahide, Dublin, on March 21-22.