<human>: Can you condense the text into three sentences or less?

Our context:
My gf and I have been together almost 4 years. We're not married by I had hoped to get married this upcoming Fall. However, things have been very strained as of the last 6 months, and I don't know how much longer things will last if they continue this way. 

She is having an episode of depression brought on by low self esteem, limiting beliefs, and arguments that have happened between the two of us. We love each other very much, and although we have been on the rocks, we still want to fight for our relationship. 

As of the last 4 months, my gf is distant, and has almost no sex drive. She won't touch me, flirt with me, or even initiate any kind of physical contact. I feel like our relationship dynamic has become almost platonic. At first I was afraid that she might be cheating, and I've come to the conclusion that she isn't (which is almost more troubling in a way...). I feel ugly, unappreciated, and extremely frustrated. I am so worn down from being constantly rejected in my advances for my beautiful gf. We used to be very sexual and I felt very close to her, but now I feel very insecure. She says that she isn't even feeling inclined to masturbate on her own these days. 

I've talked with her numerous times about this, about how she treats me, and how it makes me feel. She's always apologetic, and says that she will try, but nothing comes of it. One of the reasons that I haven't left the relationship because this all has been so sudden (as of the last 4 months), and it has all coincided with her lack of self esteem. 

Ladies, and gents that have been in a relationship with someone with severe depression, please offer me some advice on how to deal with this. I'm not a genius, and I am at my wits end. Do things get better? How can I keep things alive?
<bot>: My depressed gf has no apparent sex drive and doesn't express her attraction for me anymore. I feel hollow and worthless. Almost like a crying shoulder, but with no actual connection in the relationship.