My fiancé found out that I want to break up

About me: 29 years old have a 3 year old son (not related to my fiancé).

About my fiancé: 34 years old wants to be the father of my son.

Our differences: different backgrounds, different cultures, different social classes, different perspectives in life, different lifestyles, different thoughts about the social structures, different understandings of the meaning of marriage, and most importantly looking at a different lifestyles after marriage.

Our similarities: same religious beliefs, both are vegans, at least speaks one same language (Chinese), and both are engineers in similar industries.

The biggest challenge for our marriage is money! We cannot get married unless we pay for our own expenses. He cannot afford me. I thought that wasn’t a problem, just combine what we make and combine spendings that will be all good. However, we ended up splitting all the time and I’m tired of that. I make a bit more than he does, but that’s not the point, we are at different social classes, our ways of lifestyles and spendings are just so different that we will just do a vote which side to stand on every single time, no matter what. I struggled and struggled for so long and now I think the best way is to leave each other. This is the biggest change I’ve made ever since we’ve been in the relationship. He used to threaten me to breakup every time when he thinks I’m too emotional because he knows I couldn’t breakup. Now that I decided to breakup, he found out from very tiny details, and is asking me a face-to-face talk. I agree that the best way should be a face-to-face talk and I’m happy that he found out, but what should I say during that face-to-face talk?