I'm going to my high school friend's wedding without inviting him to mine
Why are you going to his wedding?
I just want to steal his future bride and make him jealous.
It's not right to go to someone's wedding in order to attempt to seduce the bride. That's completely inappropriate. If that is your intention I think you should skip the wedding completely.
Whatever, it's easier for me to take someone else's woman than it is to get a man to love me.
I do not think that you should go if that is your only intention. That kind of behavior is unacceptable, and it will probably ruin the event for everyone involved.