let suppose the guy is very handsome and has very good facial features but his head is proportionally bigger than normal... would you marry this hot but big-headed person?
You SHOULD feel attracted to your potential partner and if you don't.....if his big head is seriously distracting you from his other more positive qualities (both physical and in his personality).............then move on and look for someone else.
If it's not such a big deal and you can overlook it, then go for it, marry him.
If you've created a thread about it....then it seems to me that you're struggling with this.