I'd say the same - I know a couple who have been through something similar. Were together for years, then got married and had a baby in quick succession. Then it was lockdown for the best part of a year and they completely lived in each others pockets while dealing with a newborn.As someone who has had kids, and all the stress and strains that puts on a marriage in the early days, I would’ve definitely sought counselling and “stayed together for the kids” a little longer than 18m if it was something work-through-able. Which is what makes me think it was something unforgivable/a failed bandaid baby.
It put some strain on their relationship but she said that she was hesitant to make a decision in the midst of such an unusual event. She had to see what their lives would be like when things went back to 'normal'. Things seem to be on the up for them again now.
Obviously we don't know the cause of this split, I guess it must have been something irreconcilable for them to make this decision, with A being so young. They both seem level-headed and not particularly rash people.