Sheila had enjoyed life and she certainly enjoyed modelling prior to her marriage.
She wasn't a model prior to her marriage;
So that was the beginning of our relationship; our life together was an endless run of intense passions and stormy differences – pathos, pain and wonder. A second pregnancy (the first having been terminated six months into our relationship while I was still a student) led to our wedding. With my encouragement, Bambs had by then
become a model and I, with hers, an advertisement sales executive. Art school had fulfilled my need for a qualification and training, but couldn’t support the expense of a wife and child – well, that was my excuse. I, basically, didn’t have the courage or strength of character to make a go of it as an artist.
Caffell, Colin. In Search of the Rainbow's End: Inside the White House Farm Murders (p. 29). Hodder & Stoughton. Kindle Edition.
Perhaps it had more to do with the number of children she lost.