USA citizen denied entry into UK-plan to marry a dual nationality British-French

It is terrible I was denied from UK last May.  :\\\'(I applied for the wrong working visa, the one for commonwealth citizens is the one applied for and they denied me because of this saying that I could not work in the UK. I contacted the Uk consulate in Los Angelos to ask if I could still come into the country for a visit and they said it would be no problem, then when I came I was held in the airport for 5 hours being interagated about what my plans in the UK. I had only a one way-ticket at the time so they were unsure of when I would be returning to the USA, and I have a boyfriend who is dual citizenship of British-French nationality so they said I was never going to leave....    Now, we are living in France and want to get married here, after our plans are to move to the UK for me to start school there and for him to work. But the problem is...if we get married in France will the UK accept me to enter into the UK as an person married to a French citizen and British citizen?? Can they deny me anymore?? Can he add me onto his British passport if we are married on his French passport??? Can he add me to his UK passport and then we can move to UK and do I need to apply for an entry clearance even after all of this? How long will it take for me to be able to come into the UK legally after I am married to him in France??? How long would it take for me to be able to attend school there being considered an EU national, not as an international student???  Can they really deny a person married to an British citizen to come into the country??? I can find nothing for information about this, we have tried to go to all the embassies, ask all the British consulates and no one wants to help us, it is very hard to live in France now not being able to speak the language and wanting us both to go to the UK for it to be easier for both of us there...thanks for any comments we are in desperate need and running out of money here, and also it is very expensive for us to always be in limbo going back and forth to each others home countries...

This all sounds fairly straight-forward.  You were refused entry as a visitor because they thought you might stay.  But the ground rules for settlement are different, so based upon what you have written, there's no reason to expect major difficulties.

If you are married and living with your husband while he exercises treaty rights in France for at least 6  months, Singh kicks in and you're ok in any case.  But I doubt it will come to that...