I think to be fair to her, communication is key. These disconnects and feelings you're dealing with are not your fault and if you love one another and communicate openly, she may be able to work through them with you. Are you seeing anyone for these feelings or taking any medications?

As for wanting to remain friends if things do go south, that's a sound idea and again just comes back to communication. If you just end things one-sidedly with no explanation and without putting any work in, I'm not sure friendship is in the cards. So just try to communicate with her and seek help if you can. Whether or not she can "handle" a breakup might not be something you should concern yourself with because keeping things going just to spare somebody's feelings can be equally, if not more, devastating in the end.