I absolutely loved this page: "What is wrong with Catholicism?" I feel like there is much more political based things wrong with Catholicism, but I like how you kept it as "What is wrong with the teachings." I loath the Catholic church for the many reasons posted on your page. I am deeply saddened to say, my girlfriend, whom I love, is very strongly brainwashed into the twisted religion that Catholicism is. She gets really offended when I talk poorly about their beliefs and I never really know what to say to convince her of my point of view. Can you please help me? Your page is great, but I don't know how to put all of that into a nice little package.
Whenever you talk to anyone about religion, it is easy to give opinions but it is harder to prove your point. If all you state is what you think, then your thoughts are just as good as her thoughts and she has no reason to accept yours over her own. But if you keep your points to what God says, then it becomes much harder to retain your own views when you can see that they differ from God. "If anyone speaks, let him speak as the oracles of God. If anyone ministers, let him do it as with the ability which God supplies, that in all things God may be glorified through Jesus Christ, to whom belong the glory and the dominion forever and ever. Amen" (I Peter 4:11). That is why you see my answers dealing with doctrinal issues and not political issues (which are opinion based).
So when talking to her, find one point to discuss, learn what God says about it, and then point it out to her in her Bible. If she is interested in following God, she alter what she is doing to conform to God's teachings. If not, you've learned a bit more about her.
And that is something you have to think long and hard about. You tell me that you are deeply in love with someone whom you don't agree with in regards to religion. So what will your marriage be like, if you do marry her? Are you going to go your way while she goes hers? What happens when the kids come along? In whose religion are they going to be raised? What is going to happen to your kids' faith when they see that mom and dad can't agree about what is right?
Then you need to understand that in Catholicism a marriage to a non-Catholic is treated as a second-class marriage. Catholics teach against divorce, but they do allow the annulling of a marriage and such is frequently used when a Catholic is married to a non-Catholic.
Differing religious views will lead toward a miserable married life. I would not wish that on anyone. Some manage to make it work, but it is never ideal. I hope you'll think about it before you and she decide to get married.