I had the impression it was a speculation/interpretation of hers (given how the marriage turned out, and also the life of the sister who I dimly recall was even more miserable), since I don't recall a citation or passage from a Heinrich letter in either book. Though I read the wives book only once, and a good while ago, though maybe I'm misrenembering, and you'll find such a passage.
She thinks Heinrich may have tried and failed to sleep with Mina on their wedding night, and that contributed to his embarrassment around her afterward.
This, otoh, I recall from both books, because she already hinted at it in the Heinrich bio as well, just more indirectly "The hour of truth had at last come" (once all the wedding festivities were done with) etc. Who knows, it's entirely possible. If I ever were to write a story in which Heinrich actually does have a one night stand with the Countess Bentinck, I'd certainly explain it by using this idea - i.e. he couldn't consumate the marriage, he wanted to find out whether this was Mina-specific or whether he could have sex with a woman at all, and he liked La Bentinck at least enough to hang out with her repeatedly, plus she was essentially the female version of his type. Also, he might have attempted to consumate the marriage because Fritz could have made it a condition for getting the freedom and the money (though I hope your story is right and he didn't demand that part as well).
Conversely, I think it's just as possible he didn't even try, and Mina didn't say anything to anyone because in ye early years, it wasn't a bad deal - she got fussed about by everyone at court, she had AW and Ferdinand for the harmless romance, and Heinrich was at this stage still polite and bothered with the occasional nice present. By the time Heinrich started with the bad behavior (i.e. after AW's death), it was too late to go for an annulment on the grounds of non consumation, if she wanted to endure the scandal, or to try and appeal to Fritz or anything like that.
Re: No Pity for the Wives readthrough - Intro
She thinks Heinrich may have tried and failed to sleep with Mina on their wedding night, and that contributed to his embarrassment around her afterward.
This, otoh, I recall from both books, because she already hinted at it in the Heinrich bio as well, just more indirectly "The hour of truth had at last come" (once all the wedding festivities were done with) etc. Who knows, it's entirely possible. If I ever were to write a story in which Heinrich actually does have a one night stand with the Countess Bentinck, I'd certainly explain it by using this idea - i.e. he couldn't consumate the marriage, he wanted to find out whether this was Mina-specific or whether he could have sex with a woman at all, and he liked La Bentinck at least enough to hang out with her repeatedly, plus she was essentially the female version of his type. Also, he might have attempted to consumate the marriage because Fritz could have made it a condition for getting the freedom and the money (though I hope your story is right and he didn't demand that part as well).
Conversely, I think it's just as possible he didn't even try, and Mina didn't say anything to anyone because in ye early years, it wasn't a bad deal - she got fussed about by everyone at court, she had AW and Ferdinand for the harmless romance, and Heinrich was at this stage still polite and bothered with the occasional nice present. By the time Heinrich started with the bad behavior (i.e. after AW's death), it was too late to go for an annulment on the grounds of non consumation, if she wanted to endure the scandal, or to try and appeal to Fritz or anything like that.