How long have you been with your partner? Has he had partners before you?
We know that in 90% of people, HPV clears from the body within 2 years. In others, it just takes longer.
If you've been with your partner for a lot longer than that, though, chances decrease that it's a long existing infection, and become more likely that it's new.
It's really hard to say if he's cheating on you based on this alone. Based on it being 2 years, exactly, since you got pregnant with your first one, it's a possibility, but it's not a definite.