A Normandy crew harshly puts it: "It is like death follows her around." Read various people's negative reactions toward Ashley. I agree - Ashley is hard to fall in love with. Negative. Stereotypical. Dumb. Problematic.
Still, tried to continue Ash's romance from ME1. Bought the right gift and said nice things. Fell relieved that Ashley "approved" Shepard and Tali in ME2. Thought about give up on Tali and go for Ashley since mating with poorly photoshoped alien is pointless.
Upon return to the Normandy (after Citadel II), a lot of people visit Shepard's cabin. Where is Ashley? Even not a new line of poem for the reunion? Very disappointed. All Ash has in her star observation room was "Good to see you, Shepard." Even no unique dialogue?!
Finally, her "loyalty mission" came - to comfort Ashley watching her sister mourn. So weak, compared to comforting Cortez for losing his husband. Fortunately, less harmful than listening to Cortez' husband's recording.
Then Tali came on board and immediately came to Shepard's cabin. Still totally worth it.