Well fwb only makes sense if you enjoying the “benefits”. If that part is no good for you (from what you described)then there’s no point in being intimate with the person.
Sometimes people just don’t click on a romantic level, no chemistry so to speak. It doesn’t matter the height or size of his whatever or his hair. You either click or you don’t. If height and size and hair were determining factors for romance, then only gorgeous tall men with huge ….you know what and hair in the right places would have a happy love life. But that’s just not the case.
If you don’t click, then you don’t click. Just not happening.