Mediation is not for 'when all else fails'. There is much useful experience available through your mediator to prevent conflict and to resolve it when it arises. We can put you in touch with mediation services if you wish, and will suggest it, when it seems appropriate. Make no promises you cannot keep . Make little promises, and keep to them - exactly.
Separation happens amid a breakdown in trust.
Not turning up on time for contact, or not having the kids ready makes matters worse. Unless trust in your word is restored, the contact will eventually break down. We often recommend that parties take the level of contact that they would first want, then halve it. In between these times, if all agree, additional contact can take place. This allows people a bit of space to make a new life, turns promise breakers into promise keepers, and allows variation without promises being broken.