Boyfriend invited me to best friends wedding but it’s expensive

So my boyfriend (27M) invited me (24F) to a wedding he’s a best man at. It’s about $500 each for travel and stay. I’d also need a dress, wedding gift, and I’m sure we’d do some exploring around since it’s a 4 day stay. I can’t afford this at the moment. It’s his first wedding ever and he hasn’t been in a relationship in a while, so I don’t think he knows how to go about this. He also makes about $120k more than me and hasn’t offered to pay for me to attend. My family thinks I shouldn’t go unless he pays. We split most things normally but this is a trip I wasn’t prepared for.

Should I ask directly? I feel awkward about this. Has anyone else been in a situation like this?