Keep-fit centre manager Lyndsey Higgins, 30, was found dead by businessman Martin Westwell after he failed to get a reply to his "done what?" message back.
An inquest heard today she had met the former fireman on a dating website.
Privately-educated mum-of-one Ms Higgins would cut her arms and had warned her boyfriend she would cause further harm to herself if they split up, it was said.
She met Mr Westwell, 44, via a dating website in January 2014 after splitting up with the father of her young son following a 12 year relationship.
Miss Higgins initially moved in with Mr Westwell and managed his gym Westys whilst he ran a motor repairs company - but she ended up getting a flat nearby where she would stay following arguments.
And they had rowed on the night in question.
On December 18 2015 - after the couple fell out in a petty argument over what Mr Westwell described as ''silliness'' - Miss Higgins texted him saying: ''I’ve done it''.
When the dad-of-one texted back and failed to get any response, he went round to her apartment in Barnoldswick, Lancashire, to find her hanging from a banister rail.