If one wears a condom, since it prevents actual "skin-to-skin" contact, would this prevent forbidden relations? I am not asking about wasted seed, but just the relation itself. Thank you
Maharsham, Rogatchover Gaon and Rav Ovadia Yosef all rule that even with a condom it is called sexual relations. Interestingly, the Rabbi Dovid Lau (a nobody compared to the heavy hitters mentioned above) has a piece in his sefer where he calls into question some of the halachik mechanics in this case, but even he stops short of saying that it's not called relations.
(source: המקום מרחק על מסכת יבמות ג' ע"ב)