I assume that it is still considered from the Kaba'ir for a man to commit Zina by having sex with a woman even if he's wearing a condom, correct?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The Muslim scholars define Zina (fornication or adultery) that it is the penetration of a glans penis of a sane pubescent person into a forbidden vagina (i.e. other than the wife).

In addition, it makes no difference whether the epidermis of penis touches the epidermis of vagina or not; i.e. it is the same ruling whether or not you are wearing a condom.

Know that Zina is among the major sins and the person who commits it faces a severe punishment.

Allah Says while describing the pious Muslims (what means): {And those who do not invoke with Allah another deity or kill the soul which Allah has forbidden [to be killed], except by right, and do not commit unlawful sexual intercourse. And whoever should do that will meet a penalty. Multiplied for him is the punishment on the Day of Resurrection, and he will abide therein humiliated - Except for those who repent, believe and do righteous work. For them Allah will replace their evil deeds with good. And ever is Allah Forgiving and Merciful. } [Quran 25:68-70]

Allah knows best.