Two parties is a design flaw of first past the post. There can be regional parties, and occasionally re-alignment elections, but the natural outcome of single member first past the post elections is two big-tent parties with roughly 50% of the seats each.
You need proportional representation or multi-member districts to have more than two stable parties.
You're mistaken if you believe they need a non-fabricated reason. The Reichstag will burn on schedule.