Reb Yankel,
I hope you had an uplifting Yom Kippur and may you merit a successful and clean year! Today by mincha we read in the Torah כמעשה ארץ מצרים אשר ישבתם בה לא תעשו וכמעשה ארץ כנען אשר אני מביא אתכם שמה לא תעשו ובחקתיהם לא תלכו.. ושמרתם את חקתי ואת משפטי אשר יעשה אתם האדם וחי בהם אני יהוה. It's hit me how only when Hashem talks about illicit sexual relationships does he feel the need to emphasize that be restraining ourselves to only what's designated to us, we will truly live. Nowhere else is this term mentioned.
Anyways, back to your struggle, I truly understand you conflict and can relate to it as well (hey, I haven't gotten married too long ago..). From one side, for you to grow, you better get married. On the other hand, in your current state, had the girl truly know you, she wouldn't marry you. There's a famous joke about this old nerd in shul who never got married, claiming that he doesn't wanna marry someone that is so crazy as to wanna marry him. But he's the deal; had you truly known the girl, with all her flaws and shortcomings, I can almost promise you you wouldn't marry her either. Most singles, girls and boys alike, are self centered individual who have seldomly ever sacrificed anything for others or truly worked on their character. And that is the point of marriage. Marriage gives you the opportunity to work on yourself (if you choose to do so). It is ok to come into marriage as a raw individual, that is why you are indeed getting married. Since we are both raw individuals, let us get married so we can transform ourselves together. Getting married struggling with porn is as deceiving as getting married self centered. It's is the way we are created, most of your yeshiva pals struggle with it too, and the most effective way to give it up is when married. If she expects to marry a malach (that is a bachur who doesn't struggle with porn etc) she is living in a big illusion.
That it not to say that you shouldn't start working on yourself now. Just the opposite. The more you watch, the more addicted you will become, the harder it will be to stop. All I'm saying is that waiting might not be a wise idea.
I hope i added some clarity (it definitely helped me stay clean tonight