M.B.
I second Laura's opinion - it sounds like you're not quite ready and although it seems like it's been a long time that you've been nursing (well done on that!), when you look back a few years down the road, you'll see that it was indeed such a short, short time. I nursed my oldest (now almost 14) until he was just over 2 and he weaned on his own as my milk went away when I was pregnant with his younger brother. His younger brother nursed until he was over 3. As time goes by, the nursings will become more and more infrequent. For my boys, it was really an incredible source of comfort whenever they suffered a trauma (i.e, falling down, bumping their head, sticking their hand in a cactus, and all the other things boys will do).
In hindsight, those years are so very precious to me and I truly cherish every minute that I spent nursing them. My kids overall were incredibly healthy, even though I've worked since they were 4 and 6 mos old and they were in daycare (their healthiness actually influenced some of the teachers at the daycare to nurse their own babies).
Your husband may be feeling neglected (naturally - not uncommon after a baby arrives), so perhaps making an effort to spend some time together without the baby over the next few months will send the message to him that you can still be a wife at the same time you're a nursing mother.
Also, as far as getting back into shape, you can certainly exercise while nursing and eating healthily is obviously good for you both. And, I think some basic multi-vitamins are healthy for you both - you just don't need any megadoses.
I did notice, though, that I could not lose that last bit of weight until I stopped nursing. I was working out regularly and I really think mother nature wants our bodies to hold onto a certain amount of fat while breastfeeding to ensure that our baby's get the healthiest milk. And, I did finally lose those extra 10 lbs - just be patient - that's been one of the hardest learned lessons for me as a mother.