Although Capricorns project authority, power, and a stern, serious disposition, underneath it all they can be like fearful children.
Some Caps cannot handle rejection. Even the slightest blow-off or critique or that great idea they had and they can be fighting back tears (or their temper).
This doesn't fare well in romantic affairs, which inevitably become heated. You can't always agree with your partner, and everyone has flaws. Any mate with serious potential will challenge you.
That means you need to relax and accept some negative feedback here and there. They aren't rejecting you or even a big part of you - there's just a few things you both need to compromise on!