Gf (29f) caught me (32m) masturbating to porn while she was sleeping and is leaving me.

I'm sure a similar story has been posted before but I'm just beside myself on what to do at this point. As the title says I was servicing myself while my gf was sleeping next to me. Our sex life is great and we just had some amazing sex the night before which was our anniversary. We have a 10 month old who still wakes up throughout the night and needs tending to so we both are pretty tired at times.
Last night was one of those nights where he was up for a while and after rocking and nursing he eventually went to sleep about an hour later. My gf fell asleep no problem but I was having a little more trouble so I decided to jack off. My gf woke up unfortunately and told me "if I wanted to have sex I could've just asked" before storming to the couch. I apologized but she wasn't having it saying we're done. We've been together for over 2 years and I planned on proposing in May when we had a trip to the Bahamas planned.
In the morning she called the resort and canceled our reso and also canceled our family Xmas cards we planned on sending out as well as began calling around for a new place to live for her and our son. I tried to give my side about how I was tired and I know she was tired and I just wanted to handle it quick and fall asleep but she feels as though I'm cheating on her. She still feels self conscious about her post baby body even though I tell her all the time how beautiful and sexy she is.
I really was just trying to fix myself real quick and get back to bed but she isn't taking that for an answer. I love her. I love our family and I just want her to know it really was nothing to do with me not wanting her. I just don't know what to do as I don't want this to break us up but it seems her mind is made.
Tl;dr I was jacking off while my gf was sleeping. She caught me and is now making plans to leave me although I explained that I wasn't trying to hurt her. What do I do?


Source.