If she loves you, you may be very very surprised to find out that she may already "know..." On some level, we survivors leave telltale traces in our interactions with others that are unmistakable markers. If your dear one doesn't already recognize them, she nevertheless must have some questions about the way things are between you that she, herself, is afraid to bring up. Once you break your silence, she will finally understand what has been mystifying her.
If I am not for myself, who will be for me? If I am only for myself, what am I? If not now... when? --Hillel