It's the tense up response that is causing your problem. You need to stay relaxed. When you tense up you input a steering response or resist the bike's natural response to the wind and it rightly feels scary to you.
Gusty winds are not fun.. I don't really enjoy riding in them, but once you get used to the idea that the bike will look after itself with minimal input from you, you lose the anxiety factor that makes you tense. Its possible to ride a straight road in a nasty gusty crosswind simply by shifting your weight on the bike as I described in that thread. Yes the bike wanders a little, but not enough to be a concern when steering simply by weight shifting. How much easier would it be to correct your course GENTLY using the handlebars? Its the quick, hard, jerky steering response that causes trouble in crosswinds. You can actually break your front tire loose doing that.
2004 Rebel 250, 2003 BMW K1200GT (roadburner), 2004 BMW R1200GS(all purpose),
1973 Norton Interstate (in a box in the basement)
1968 Triumph Bonneville