First of all, you are totally normal! I would say that my husband and I have sex about once a week, and I am perfectly content with that. I'd be content with less, truth be known. I almost never can stand having sex in the evenings because I am so tired and my husband's face is so scratchy by the end of the day! I am a daytime kind of person, which only leaves us with weekends. In fact, on weekends I occasionally try for twice in a day to make up for the previous week. I know my husband would love it more often, even NEEDS it more often. And quite honestly, I think I need it more often too. It's hard for me to really enjoy it, and that's something I need to work on. If I enjoyed it more, I'd be more willing to give it to him more often.
Being seven months pregnant, getting up at 5, working part time, taking care of a little one who is really still a baby too . . . I think your husband needs to understand that it's hard for you right now.
That being said, I always heard that for a successful balance to be found in a sexual relationship that the man needs to do it less than he wants and the woman has to do it more than she wants. It sounds like your husband is doing his part, are you? Remember, you asked him what he would change about you. Did you really want to know? Are you willing to put forth a little more effort? You obviously love him intensely and want him to be happy. Yeah, it's a sacrifice sometimes, but isn't he worth it?
Sometimes if he needs a little boost (it's amazing how sex can have such a positive influence on a man's stress levels and emotional well-being) then you don't have to have full intercourse. You can be there for him, and help him feel good, without the pressure of coming yourself. Now, I know some people would have a huge problem with that, and if that was how it was regularly, I wouldn't recommend it. I think it's important for a woman to enjoy herself and for making love to be an equal experience, because that is so much more bonding for your relationship. But the occasional time that is just about him shouldn't be hard to do. I don't feel like I'm "servicing" my husband. I love him and want to please him.
It's hard for us women to understand, but the more sex a man has, the happier he is. And let's face it, the happier he is, the happier we are, the better our marriage is, the happier our family is, etc. etc. So commit to twice a week. I will too. We can do that. Our husbands are worth it, and so are we!