Semele was just a priestess who got diddled by Zeus, as you do, and got pregnant with Dionysus.

However, after shenanigans by Hera, she got tricked into asking Zeus to show himself to her in his full godly might, and because he was oathbound due to earlier power-of-boner stuff, he had to unwillingly comply.

He tried his best to show the tiniest sliver of his true being that would count, but she was still mortal, and got burned in godly flame for just witnessing him.

Zeus, saved the foetal Dionysus by strapping him to his thigh until the thigh-pregnancy was complete, and later, Dionysus found his mom in the underworld, and made her into the God of Drunk Frenzy.

Following all that, Semele appears to be uppity about her incredible husband to her sister, because Semeles husband carried their fetus to term after Semele died, while her sister's husband was a mere wife-and-son-murder-attempter.

I love out of context ancient greek mythology. Btw, all that, makes Dionysus the only god in this graph, apart from Gaia herself, to not be the product of direct incest. (Is brain-parthenogenesis incest? Who knows)