Let's just say it was all painfully surprising. After Viserys' death, life changed a bit - especially when Alicent and Rhaenyra decided to take on the business together, leaving Aegon, unnerved by possible responsibilities, finally alone. Alicent realised that... she was just tired. Constantly spending her whole life for the sake of this family, when everyone still liked to remind her that she wasn't even a Targ anyway
And so her official resignation took place. Then she finally went on holiday somewhere on her own, then she somehow wandered into one of Aegon's awkward parties, then she accidentally slept with some teacher of his....
Wait, what-what?
Okay, just kidding, you weren't his teacher anymore! I mean, Alicent took care of everything. Why would you even want to work now?
And maybe it wasn't so accidentally - objectively you knew each other by then. Your husband left you after a long and unhappy marriage, and that's how you girls found each other in grief. Alicent never thought she could have been so wrong for so long in her life.
Her resignation ended up being almost the best decision of her life. Now you were living in the Targ family mansion, and even though every relative had their own opinions about Alicent and your stay in the family..... You were almost fitting in. But in some way, Alicent finally didn't care, and she was just happy.