I am going to define largesse as a feeling of generosity arising out of gratitude and well-being.
The idea is this. You are supposed to be a Goddess, or a Queen. He should be treating you that way, including being obedient and doing what you want.
Of course, if you have never been treated as a Goddess/Queen, it is difficult for you to imagine how that will make you feel.
But, at least in theory, you will feel content and happy. You furthermore will feel gratitude. And, out of well-being and gratitude comes generosity.
One dominant called them "boons" -- she granted boons to her loyal subs. A boon was a favor granted by the king or queen to a subject for meritous service.
This is mostly something that just happens. You shouldn't try to make it happen; you don't need to know that it might happen. However, it is worth mentioning because it is potentially useful in bridging the gap between what you want to do and your husband/boyfriend's submissive fantasies.
The idea is this. Your husband enters the dominant/submissive relationship with submissive fantasies. You enter the dominant/submissive relationship with your own desires. Perhaps those include some of your husband/boyfriend's fantasies. If so, lucky him.
If not, it is natural for you to get your way, because you are the dominant, and because neither of you should be doing something you don't want to do. Also, some fantasies are harmless, but perhaps some are not.
In a "conventional" relationship, a compromise would be fair. He should understand that compromise is not appropriate if you are to feel like a dominant. So not satisfying his needs is not fair, in a way, and both fair and necessary in another.
This is where largesse comes in. If he can help you feel like a Goddess/Queen, you might feel largesse. He shouldn't feel like he deserves that, and you shouldn't think you have to feel that way. But it might just happen.