Piglet, what good is she doing by her actions?
There is a huge difference between a public statement of hurt and disappointment at the ending of a marriage (and tbh, I'd be very surprised that any one outside the two individuals and their immediate family would care) and what Alice Evans is doing.
She is being abusive to a woman she doesn't know, accusing her of 'stealing' her husband 
when there is no evidence whatsoever of an affair - and within celebrity circles/gutter press journalists you can bet if there was even a hint something would have made it into the gossip columns.
She is whipping up her fangirls into a frenzy and encouraging them to go looking for information on Bianca which she can use in further abuse.
She appears to be drunk tweeting in the middle of the night, most of the night. He has accused Ioan Gruffud of not caring that their nanny is seriously ill - she herself appears to care less, I would suggest that she is not in the best place to be caring for her children in her current state, therefore putting more of the burden on the unwell nanny.
Her children are seeing her behaviour. They are seeing her call their father every name under the sun. If he manages to maintain a long term relationship with Bianca, which I seriously doubt having seen Alice Evans' behaviour, his daughters will probably reject her due to their mother's libellous ranting.
The divorce petition sights parental alienation so her behaviour appears to be longstanding.
She is using her two young children as pawns. She is proving herself a liar, unemployable time and time again.
What she is doing is helping no-one, certainly not women dealing with relationship breakdown.