i was about to suggest a strap-on as a reply to one of your earlier posts. Perhaps she is just not that size-queen type. What about a medium or even smaller sized dong used as a strap-on? Perhaps she will be more open to that. On another note: maybe she doesn't like the big ones because she does not want to hurt your feelings. i understand that that's not how you tick but does she understand that as well? ImO you should explain to her exactly why you think a bigger d. would be beneficial
for you, not only for her.
If she doesn't want to watch p0rn (yet) there are more than one possible reasons for that. But there are also other venues to try. Have you tried
erotic stories yet? Other than that there are a lot of sex/adult
podcasts out there. "Consenting Adults" deals with the many faces of "ethical non-monogamy" and is quite good. The "Keys and Anklets" podcast and "Cuckoldress V" are more specialized in "Hotwifing" and "Cuckolding". But there are plenty more. Perhaps you suggest to search for one together and see which one she will like?
Or tell her to look for a podcast of her liking on her own that you can then listen to together. i always enjoyed big time doing things like that. You don't have to bring up a topic by yourself, it is presented by the podcast host and guests and provides a lot of material for your discussion or pillow talk after listening, plus you learn new things too.