In the following sentences, formal usage requires the subjective case
(I, he, she, we, they) because the pronoun would be the subject if a verb were supplied:
You are more responsible than he. (in full,
...than he is.)
Informal usage permits the objective case:
You are more responsible than him.
Formal English uses the objective case
(me, him, her, us, them) only when the pronoun would be the object if a verb were supplied:
I thought you preferred John to Mary, but now I see that you like her more than him. (which means
...you like her more than you like him).
Just watch out what you really want to say:
Martha and Jason like spending free time with eath other. I like spending free time with them too.
However, Martha spends more time with him than me. (Martha doesn't spend as much free time with me as she does with Jason.) or (Compared with Martha, I spend less free time with Jason.)
AMBIGUOUS
However, Martha spends more time with him than I (do). (Compared with Martha, I spend less free time with Jason.)
UNAMBIGUOUS
