Responses (2)
"be yourself" that's the best advice you'd ever get. Honestly mentioning about ex bf/gf isn't a pleasant thing at all. That applies to everyone. It pushes the new bf/gf into a pathetic spot.
But, just because he talks about her(i suppose he's talking the good stuffs about her), don't try to be her. Pretending makes everything awkward. Just be yourself and tell him how you feel and solve it. (remember not to insult to his ex gf) if he still needs you, he'll try to become who you need to, if he still try to see her inside you... Just dump him. Every girl needs a man who let be herself and let do what she really wants.
Hope my answer was a help for you. :)