He's not her usual type, but she fell for him after dating for a couple of months. He fell for her on the first date. to cheat on (somebody): to secretly have a romantic or sexual relationship ...

Modals have lexical meaning unlike non-modal auxiliaries ... Traditionally verbs have been divided into transitive and intransitive. Transitive verbs take a direct object, intransitive verbs do not: ...

If an action concerns only one person or thing, you mention only the person or thing that carries out the action (the subject) and the action itself (the verb).