She is his daughter and not a lover you know why?

Here’s my 100% proof:

Alyssa Targaryen, Myseria, Rhea Royce, Laena Velaryon, and Rhaenyra Targaryen.

You know what all these women have in common? Daemon was inside all these women and they died! 100% fatality. None of them died old and peacefully. All went out young and in agony.

However, look at Daemon’s kids. All of them got plot armor. All of them came out of war physically unscathed and lived long lives by Westerosi standards. 100% survival. Not only Nettles didn’t become dragon food but was able to tame a wild dragon. She survived the sea battle that took life of Jacaerys Velaryon. By the end of the dance, Nettles is living her best life with her dragon.

The only Daemon’s kids that died young are kids who didn’t live after delivery. But if you survive infancy, you get plot armor.

P.S. that’s why Alys’ kid is Daemon’s as well. The witch knew Daemon is grrm’s favorite and wanted her kid to be cool and have a plot armor.