Yes, I think this is an example of irony. Two “friends” on the verge of separation find themselves stuck together. We expect them to separate, yet they do not. It’s amusing because they clearly can’t stand being stuck to each other.
But what about Alanis Morissette’s song “Ironic?” Is “rain on your wedding day” ironic? I don’t think so. Though you may prefer it not to rain on your wedding day, you can’t expect it not to (weather being unpredictable). You also can’t expect the apocalypse or a dinosaur invasion (these things being rare and mostly confined to alternate universes). Now the parents of the bride finalizing their divorce on the wedding day might be ironic. We would not expect a divorce on a wedding day. And it would be amusing (at least to me).
Anyway, I would say rain on your wedding day is a coincidence, not ironic. What say you?