The same thing could be said to him IMO - are you so opposed to marriage that you'd lose this woman over it?

The only reason the same can't be said is that he's had this particular perspective the entire time they've dated and he even made it clear upfront.

we don't know why exactly he's not keen on getting married, but he's allowed to have certain perspectives - especially if he makes it clear from here on out.

It doesn't seem fair to be critical of OP's desire to have marriage

this is silly, no one here is arguing that marriage is wrong at all. people are critical about the fact that OP is expecting that the guy should change his perspectives ... pretty much for no good reasons.

depending on where they live, if they are cohabiting, they might even be common law married.

we don't know what OP's expectations about marriage are, but if she wants a wedding ... that costs money.

another thing is that marriage = legal institution. if they're not common law married, then he might be more comfortable about taking certain business risks knowing that his partner will not be affect (i.e. liable) for him taking risks. this is one of the key reasons some of my close friends aren't getting married yet. we are all at a stage in our careers where we are starting our own businesses. if we get married, then our partners may end up liable because of the massive risks we're taking. given that we're not married, we know our partners can support us if things don't work out - and they aren't adversely affected by our actions.

my point is - he may have valid reasons to not get married (there are plenty). he made it clear early on. she wants him to change his view, without any convincing reasons as to why he should change.