It really isn't uncommon for us moms to lose our way when it comes to sex, men see it very different then woman do, I have gone through similar feeling over the years, and here is what I have figured out, it really has nothing to do with how attractive our husbands are or how much we love them. We become overwhelmed, I notice you have a new little guy plus a 2 year old, and they can be tiring, one is a lot more easier to work around two make it a lot harder, and I am sure by the end of the day you are ready to just go to sleep, I always jokingly say that sleep is more important to me then all the money in the world, That is my me time, what you could try to do is explain to your husband that you would just like to cuddle at night, not have sex but snuggle, talk, watch a movie, those kind of things, they will take your mind off of the list of chores you have waiting for yourself the next day and maybe you will be more receptive to the sex if it doesn't feel so much like a duty, like every night when you climb into bed it is expected of you, sex does change during a marriage once kids arrive, but if the perspective of sex is changed it can become more enjoyable, maybe not every night, but quality over quantity. I don't know if I helped but good luck, you are not the only married couple in this boat, I just wish more people would talk about so there is a more realistic view of what really happens in a marriage once children are born.