there is an absolutely huge back story to this. in summary, my friend has ME, has had it since she was 16. and has never had dcs, married, moved out of home etc (her parents kind of care for her i think) and a whole host of other physical and mental health problems that i think a lot of them are in her head
she is absolutely lovely. she is clever, funny, loyal, beautiful and a brilliant mate, one of the nicest women i know
the trouble is, she gets into relationships with men who mainly just cannot cope with all her problems. they inevitably act like twats, hurt her, dump her, or she dumps them for being twats. but otoh because of her myriad problems, she can't be the girlfriend that guys want, ie she won't sleep over their house, she won't see them more than a few times a week as it apparently wears her out, but then obviously that means the relationships cant move on naturally. the one or 2 nice, understanding guys she has been with, she dumps them for being too nice 
she is also very attention seeking, constantly putting cryptic statuses on FB (usually re latest dodgy relationship or latest health thing) that seemed designed to elicit sympathy. i can tell lately that a lot of people are getting a bit weary of her (we have a few mutual friends) i can tell just by the lack of response on FB etc. she seems to almost revel in many of her various health problems (none of which are life threatening / limiting btw). i also think she should fight it more and tbh her family, in particular her mum is quite enabling. my mum would have told me to get a grip TBH.
i have loads going on in my own life. a home to run, kids, a husband, my own business, money problems, my own mental health problems (anxiety and depression). i worry about her a lot and its all getting a bit much.
i feel like such a cow and a rubbish friend. but its getting hard for me to support her. and i really do want to. sorry this is long but i dont want to drip feed.
so i just wanted to know if anyone has been in a similar situation to either me or my friend, and has any advice for me.