Need to set boundaries

I wanted to vent annoyance about a "friend." We used to date, but he broke up with me because he was in love with someone else. Fine, we hadn't been dating more than a few of weeks. But now that he's broken up with her, he has been suggesting we get together for sex. I have been so depressed and this is the last thing I need. What I'd rather have is someone there to listen and support me, not use me. I absolutely cannot imagine being with him right now.
I woke up early at 5 am thinking about his offer. And all I could feel was anger at him. I see this as a good thing, some energy to shake my depression a little bit. 
Just venting.