She will be the one binning him.
Everyone is disposable to MM once she considers their ‘worth’ to her has declined from her very best friends, to colleagues, to siblings, to parents as well as husbands / long term partners etc.
She has no problem moving on to ‘bigger and better’ things - standing on people’s necks to get ahead is a pattern of behaviour very visible throughout her life.
Once this summer is over and The Ingriftus Games and the UK have not spun As Ever into stratospheric commercial realms - she will be considering his contribution to her financial future.
But she won’t be leaving him until she has another wealthy fool lined up. At her age and with her poor social status she will be struggling - even Jerry Hall and Jaqueline Kennedy had to marry ugly ogres decades older than themselves to ensure the cash in middle age.