<human>: Can you give me the gist of the text in a nutshell?

I'm 23M dating a 20F f0r 4 years. She has begun to act pretty apathetic towards the relationship.  Everything about the way she acts tells me that she doesn't really want to be with me anymore, even tough she says she does.  Sex is boring, we hardly talk or see each other, it basically feels like the relationship has fizzled.

I've tried to remedy this by not being clingy, working out, being more social, and at the same time surprising her with nice things like flowers and a home-cooked dinner.  At first I thought she might just be depressed, because she was saying how stale life felt/is nervous about graduating college this year, and would randomly cry but couldn't tell me why.  Now she doesn't do that so much but isn't back to doing things that make me feel like she cares.

On top of this, my roommate (23M) dated a girl (22F) about about the same length of time.  They broke up a few months ago, but she has come around a little more recently to see if they could work things out.  

We've always been friends and kind of flirty with her, but one night when she stayed over with him, she was drunk and came into my room, told me she didn't know if she should be back with him and kissed me on the cheek.  I told her she had to get out.  A week later she texted me and confessed that she has deep-seated feelings for me and not for my roommate.  I didn't really respond with much other than "why are you telling me this?"

I know it seems complicated vague, but I would appreciate some specific advice.
How can I keep the relationship with my girlfriend alive?  I don't want to loose her.
Or, how do I know when to give up?

As far as the other situation goes, how can I deal with it to make sure my relationship with my roommate isn't jeopardized?
<bot>: My girlfriend doesn't seem to be in love with me anymore, and my roommate's exgirlfriend has feelings for me.  How should I deal with this awkward situation?