A little of what Hacked said and a little of what Corporate said.
The first few months were incredibly difficult (with added stresses such as DD being premature and having various medical tests) but we clung to each other through that.
I needed DH in a way I hadn't needed him before. Luckily he stepped up. He totally understood/sympathised with how hard a time I was having at home, and helped as much as he could, rather than somehow thinking I was having a lovely time off work.
Now, as DD has got older, things are much calmer and easier. Our relationship is different - we are more tired, have less sex, far fewer meals out or time as a couple. But we also have lots of new shared experiences, jokes and priorities based on DD, which again brings us closer together. I think it helps that we were long past the "honeymoon phase" anyway before DD came along, and we'd had many years of couple dom so didn't miss it too much.
In the future I hope we'll regain more time as a couple - it is important. But we both understand that is "on hold" for a few years, barring the odd day off thanks to grandparents.