And your husband knows that, as a father, he's not supposed to feel jealous of his own baby. But subtle resentment can develop. As a mother, you've moved onto a sort of sacred, revered pedestal outside the category of women who are sexually stimulating. You may have encouraged this attitude if you wanted a break from sexual play after childbirth. Your husband may have had some strong reactions, too.
Men can be squeamish about earthy stuff like labor and delivery, episiotomies and lactation.
The idea of getting you pregnant again may have cooled him on intercourse. Talking these things through is best, but if he refuses, there are other things you can do. First, try to decrease his life pressures and financial demands, since these are the excuses he gives. Second, try to find out if he has emotional needs that have been left unmet since the baby came. Third, work toward regaining your figure and your playful availability.