I'm saying that my personal opinion is that I would want to have full control and the only access to my money until the 'other party' (male or female) has made the ultimate commitment to me, to US, by entering into a 'legal contract' (marriage). As it was at the time (we've been married over 35 yrs) I was 'slightly' the higher earner but not by much.
I guess I'm a believer in 'shit happens' as well as 'prove yourself to me'. A wedding ring on one's finger is a sign of commitment, of the person saying 'unto death do us part'. If you're just living together there is such an 'easy out' whereas divorce is HARD and has legalities around finances. No such guarantee with living together. I know, marriages fail and living togethers can last a lifetime. But I liked the 'odds' that marriage brought me all those years ago and my 'gamble' has paid off.
So technically yes, I suppose financially you might be better off under option 2, if we assume that you wouldn't have at least $500 per month left over for 'fun money' after the 'percentage split' of option 1. You'd have to calculate your monthly percentage to know what you'd have leftover under option 1 before you can judge that. If under option 1 you'd have $300 leftover, then theoretically option 2 might be better because you'd have $200 more. Under option 1 the amount HE has leftover is irrelevant even if it's $1000. Because option 1 to me is about retaining control of your finances, not about who has more to 'play with'.
Under option 2 you are giving up sole control of your finances (so is he). A joint account means that either party can spend whatever they want whenever they want. So if he or you wanted to buy something that might make things 'tight' for a month or so, or spend money on something the other disapproves of there would be nothing the other could do about it. Or (God forbid) if he (or you) should turn out to be untrustworthy and clear out the account and run off to Zanzibar, there wouldn't be anything you could do about it either, if you were unmarried.
You see, it's not all about 'pounds and pence' when one contemplates joining finances. It's about self security and financial independence. I was a full time working mum on a very good salary and kept working until I retired. I will say that IF a woman (or man) chooses to be a SAHP then joint finances are an absolute necessity, married or single. But I wouldn't choose to have a child without marriage unless I knew I was financially capable of raising that child on my own.
DH was (and is) trustworthy and honourable. I made the right decision both in marrying him and in trusting him with my financial wellbeing as well as my heart, as did he when he married me. You need to think in terms of decades, not months. And lots of brutally honest 'what if' conversations with your partner right now, before you make a decision.
Sorry for the 'verbosity', but next to having a child this may be the most important decision you ever make.