First wedding invite

What do you wear to a wedding? I know white is a no no. I’m still not sure if I want to go w my bf. It’s my bfs bff and gf getting married.

They are uninviting someone just so I can go.

It’s an hour away. People I don’t even know. Should I let him go alone? The plates are only $100 and of course I like to purchase something nice.

Let’s say I do go, what is a proper dress (please state what store)

And what nice present can I bring to wish them a great marriage.

They’ve been dating for almost 15 years so this marriage will last for eternity, the relationship has been tested multiple times and they still stick it out and now the date is nearing.

Should I go ? And if I do what do I wear and what do I gift? Thanks