With Sandro, though, I think she would have recovered her self-esteem. She wouldn't have had to go through all those humiliating & desperate attempts to find her husaband which led Willy to say she would marry 'anyone who was manly' & eventually led even QV
to consider her desperation unseemly.
Perhaps if she had been brought up with the Hessians, for example, she might have realized that marriage was not the be-all & end-all, but for Moretta I think it was - which made her all the more desperate.
I don't think she loved Adolph. Vicky wrote:
"In her depression & discouragement, feeling that the happibness she had hoped for is not to be hers, she accepts [him]"
Her miscarriage & sibsequent inability to have more children must have been truly heart-breaking for, as you say. She had been denied happiness with the man she really loved & then denied the children she SO wanted. Even when did settle with Adolph (& Marie Mallet described them as 'a most devoted couple') there came all the furore & squabbling about Detmold. Nothing EVER seemed to work out for her.
Had she married Sandro, I think, she might at least have had the one 'grand passion' - however brief - that would have brought her some satisfaction. "Better to have loved & lost than never to have loved at all..." etc.
(But then, of course, I am viewing it romantically rather than practically...as is constantly my failing

)