Learn Italian: Purtroppo abbiamo dovuto cancellare il nostro viaggio.

When using a modal verb like dovere (to have to) with an infinitive, you choose the helping verb based on that infinitive. The main action here is cancellare (to cancel). Since you would use avere for the verb cancellare on its own (abbiamo cancellato), you also use avere for the modal verb: abbiamo dovuto cancellare.

What is the exact translation of abbiamo dovuto?

It translates to 'we had to'. While the present tense dobbiamo means 'we have to' or 'we must', the passato prossimo form abbiamo dovuto is used for an obligation in the past that was actually carried out.

Why is it il nostro viaggio instead of just nostro viaggio?

In Italian, you almost always need a definite article (like il, la, i, le) before a possessive adjective. So, 'our trip' is phrased as 'the our trip' (il nostro viaggio). The most common exception to this rule is for singular family members, like mio padre (my father), which drop the article.

Can purtroppo go somewhere else in the sentence?