A Choice between Dunyah and Aakhirah

I have found on numerous occasions, where it seems that I have to make a choice, and the choice is quite blatantly between the Dunyah and the Aakhirah, whether it be a choice between a good career/academic education and islamic education, between choosing to marry a deeny man or
a rich-dunya orientated man etc.
One profound thing remains in my mind that the Sheikh in class once said: That "the Dunyah
and the Aakhirah are like two sisters, if you choose to marry one of them, the other one becomes Haram for you."
I dont believe in these kind of people who think they can have the best of both worlds. I think they are confused/deluded in their intentions. The message here is quite clear, you cant have both, Allah does not allow it.