Property purchase taxes for mixed residency couple

I am currently starting the process of buying a property with my fiancee. She is Italian and has residency. I am English and need to travel (UK and other countries) and so do not have residency. There is a chance that I may change residency within 3 years, but would not bet on this. With an aging parent in the UK this also needs to be considered as I may need to do my share. Currently this travel offers the benefit of lower income tax options (which comes in very handy when looking to set up a home). I will be a full Italian resident one day and truly look forward to living a normal Italian life (using the suitcase for pleasure only). I had understood that for split residency couples buying a property the tax for resident purchase and non-resident purchase would be split. Her share at 3% and mine at 10%. Is this still correct? If that is so, we had considered buying in her name only. But would I still be covered in case of splitting up? A friend had said that you are covered for the % that you can prove you have contributed, but they are an electrician! We have been together (not married yet - that will follow after the house) for over 10 years and have lived in multiple countries through good and bad times. I am very happy........but try to be a little cautious (especially when some good friends are divorcing after 26 years of marriage). We are going to discuss this with a lawyer and Nataio, but any guidance would be appreciated. Nervous enough as it is!!!!