I Have Been Recently Married, I Have Seen Videos Many

I have been recently married,
I have seen videos many times, but when real time came, i was not ablw to insert my penis,

I dont know whats the problem,

I believe 2-3 reasons,
My foreskin is very tight, so when i get erection my foreskin hurts and it limits my erection.

Even, i cannot last long during a good erection. Just a matter of seconds and my erection gets weak so i could not try longer for erection.

I know where the spot is, as we did a lil fingering also.
She is desperate and i dont know what to do.