Actually, it is quite reasonable to conclude that Jesus was tempted sexually as are other people. Those temptations, however, unlike every other person, did not originate from within. They were not temptations arising from fallen sinful flesh, but the temptations placed in front of him by Satan and his demons, and also other people. The phrase in Hebrews actually says “kata panta kath homoioteta” meaning “according to every respect, according to the likeness” in which we are tempted. There is thus discontinity and continuity between Jesus’ temptations and ours. First, there is discontinuity in that he was “without sin.” That is, the outcome of his temptations never ended up in sin, as ours often do. Second, there is continuity in that he was tempted “according to ways” we are tempted. I am not sure, however, that the language of Heb 4:15 substantiates the idea that he was necessarily tempted “in every way” we are.
The Law of God demands perfect obedience. To be tempted in one way, while different than others, nonetheless partakes of the same hideous thinking—to be like God and to overturn his rule. Thus there is an essential unity to all forms of temptation—they all strike at the same underlying desire. It is not necessary, theologically speaking, therefore, for Christ to have been tempted with all the temptations humanity has ever faced in order to qualify as our substitute. It is highly unlikely that he was ever tempted with homosexuality in his culture. It just wasn’t an issue. That is not to say that he cannot sympathize with people who struggle with homosexual temptations (Heb 2:18), because the root of temptation is the same—to make life work apart from God (thus becoming god’s ourselves). Therefore, he knew what temptation was all about. And there is merit in the argument that he knew the force of temptation better than we do, because the one who resists temptation knows its full force better than those who do not.