I am sure that most of us know this feeling very well. Having had three kids I have found that I'm pretty disinterested for a couple of years after giving birth. As happycat says it can often feel like a chore, particularly with the other very physical demands being made on you, by bedtime you just want to be left alone! I sometimes think it is nature's way of protecting the child you have, by taking away your sex drive to ensure you don't conceive again.
However, your feelings will come back, don't worry. They will come back as strongly as ever before as long as you encourage them. Men don't understand this loss of sex drive, and it's easy for them to think we don't love or desire them any more (in fact I often have sexy thoughts about my DH, but by bedtime I am usually past the point where I would act on them!)
Unfortunately there is great danger of men having affairs within the first couple of years of a child's life. Whatever we may think about this, I am sure it is something we wish to avoid, and I think we have to accept that men and women feel differently about this subject. It's important for both partners to take care of the other's feelings, women want to feel loved and emotionally and mentally connected before they ever get in the mood for sex, (at this stage in our lives, anyway), and it's important that we explain these needs to them. On the other hand, they need sex to feel loved and so we have to do our best to fulfil their needs too.
You would not wish your partner a life without sex, I am sure. Even if it doesn't matter to you, it does to him, and it is not fair to expect him never to have sex again. When I have felt as you do, I try to make the effort now and again, usually on a weekend morning or afternoon, when I had a bit more energy. Sometimes when I did not feel interested I became interested as it went along, if you know what I mean. As time goes by and your energy levels increase again, your drive comes back and things fall naturally into place if the framework is there.
A night or two alone is a fantastic boost too, if you have a kind friend or relative who will relieve you of kids once in a while.
It isn't just for your partner, it's a pleasure in life you shouldn't be missing out on either - I hope you find it again.