I am in a quandry!

I have a DD 13 months who I am lucky enough to be a SAHM for and am really enjoying.
I have always wanted to have a minimum of 2 children as I come from a big family and feel a desire to give my children a big bosom of a family to grow up in. I feel very strongly about the idea of siblings and have been considering planning for a second baby from the moment DD arrived.

She was a relatively easy baby (not what I had expected at all)and apart from a bit of a difficult patch at about 8 months has remained so. I would dearly love my children to be very close together in age so I am seriously considering trying for a second baby asap.

Its just that.....
my DH,
although I love him and he LOVES DD, myself and the family unit,
is REALLY unsupportive in day to day life. He is just so busy with 2 small businesses operating which require his constant attention. He is really bad at prioritising me, he is just flat out, unable to do it and we have argued about this a lot in the past. We are currently undergoing counselling about this as I feel it is really important to be supportive to me and to DD and to set a good example of a healthy relationship for our girl. However, in general, I just make the most of my situation and have been doing the parenting pretty solo since pregnancy. Mostly I cope, but I am really worried about doing it with 2 children.

What I want to know is, considering that in all honesty he is not going to change (as much as he may in some ways wish to) should I just try for a second child? Can I manage it on my own? Have others been there, done that? Did it work or was it too much???? I know that there are a lot more men out there like my DH, our society is really good at helping to shape these men!!