Sex drive

Ever since I have had my last child my sex drive has plummeted. Like my husband and I were having sex 5 times a week and now its like 2 times a month and I want to always but my body is like nope. My husband feels its him and I keep telling him its not and we dont have the money to go to the dr and im not sure what the problem is im only 25 my sex drive should be great. Has any one else had this problem?