Will I be tired of nursing for the baby?

Ages ago I had decided to nurse DD until she was 2 (or thereabouts). She's
2 in January and still loves it. We've cut back a lot - my suggestion not
hers and she often asks to nurse, at which I just delay it for as long as
possible, (how about after the bath, let's have a cuddle first etc etc).
I'm pregnant with Number 2, due late March early April some time. I've read
enough articles and posts, and knowing DD that I'm pretty sure even if I
managed to wean her when she's 2, when the baby comes along a few months
later she'll want to start up again. So I was thinking instead I'll just
keep on the way I am, but keep slowly winding it back, and maybe phase it
out after the baby arrives and the novelty has worn off - does that sound
like a plan?
The problem is that I'm really feeling sometimes that I've just had enough -
and it hurts quite often - I guess because of the pregnancy and although I
plan on just powering on I do worry that I won't have the same commitment to
feeding number 2 as I'll just be so sick of it - or will I feel different as
it will be a brand new little one?
If I plan on taking that one to 2 years it will be just over 4 years of non
stop nursing - I love it in principle, but feel like in practise I've had
enough.
Any thoughts?