Hello David
You're seemingly new to the board (welcome) so it might be an idea to peruse existing threads relating to the Thayers - a good deal of information on both Marian and Jack in their later lives can be found there and it seems a bit futile to duplicate it here.
I do agree, though, that Mrs Thayer is one of the more attractive
first class passengers. Like you, I've been drawn to her because of her good looks and glamour: you might be interested to hear that the photograph you mention above was one of several taken in one sitting; I've seen another shot from that session, with Marian seated in a different pose, sans tiara.
I don't believe that Randy Bigham is still posting on the forum (his profile has been deleted) but he once added a memorable quote from a magazine published in the winter of 1912, in which Marian is described as 'the most splendidly fashionable' woman in Philadelphia Society. As you'll know, she and her husband ran with a very glitzy crowd and were guests at the exclusive Widener dinner in the a la carte restaurant on the evening of Sunday, 14th April. We know that Marian was a friend of the bereaved Emily Ryerson and showed great kindness to her during the voyage. She was also close to Eleanor Widener and Lucile Carter - I've added quite a lot of information about both these women to the board over the past few months, so I'd point you to the relevant biographical threads under 'Passenger Research'. Likewise, I've provided a bit of general background on the Thayers on the 'Rich People in Society' thread under the heading 'Gilded Age'.
I'd agree that not much is documented about Marian's life after the 'Titanic'. The impression is that she did withdraw rather from the social round - and, yes, family members do seem to agree that she spent a lot of time cooped up in her gloomy mansion, experimenting with ouija boards or something similar. She WAS present, I believe, at Madeleine Astor's lunch for Captain Rostron after the disaster and a day or two later entertained the captain at her Haverford home. Her neighbour, Martha Stephenson, who had also made her escape in Lifeboat No. 4, was present too.
Are you aware that J. Bruce Ismay developed something of a crush on Mrs Thayer and the pair wrote to one another frequently after the sinking? He saw her as something of a 'soul mate' and his letters became so intimate in tone that Marian thought it best to (gently) discontinue the correspondence. This episode is fully described in the Ismay family memoir, 'A Voyage Closed and Done'.
Brian Ahern is a great authority on the lives of the
first class passengers and will doubtless chime in here if he can add anything new. In the meantime, if I were you, I'd root out the existing threads I've mentioned above.
Regards
Martin