You’re Marrying the Wrong Guy
You have to wonder if this maid of honor was sober. Having a male maid of honor is not the norm but breaking traditions is exactly how we make new traditions. One thing that should always be consistent though is that the wedding is very much not the place to declare your love for someone elses’ betrothed.

If he was truly in love with her, he would have taken literally any other moment to confess his true feelings. Ruining her wedding day by making it about him and by speaking ill of her brand new husband, is literally one of the worst ways to express your love for another person.