Does this truly refer to adultery?
Radak: This is always a metaphor for idolatry.
Malbim: Yes.
What is "Mitzhalosecha"?
Rashi: It is the joyful neighing of horses engaging in Bi'ah 1 .
Radak: You rejoiced over your evil deeds.
Malbim: Your rejoicing over your adultery, which publicizes it.
Radak: This is like it says about horses "v'Yasis b'Cho'ach" (Iyov 39:21).
What is "Zimas Zenusech"?
Malbim: They are your deep thoughts of Zenus.
Why does it say "Al Geva'os ba'Sadeh Ra'isi Shikutzayich?
Malbim: Also after you left the city to exile and dwelled in the field, you did not abandon your abominations (idolatry). Also there I saw your abominations in the field, openly, like they burned [children] to Molech in Egypt.
What is the question "Lo Tit'hari Acharei Masai Od"?
Rashi: When will you purify yourself?
Radak: You will not purify yourself after becoming Tamei. And if you say that you will - when, for you did not do so before being exiled!
Radak citing Targum Yonasan: You will not purify yourself until many days pass.
Malbim: Also after the Churban, you will not purify yourself. When will you purify yourself?!