Just like puppies and kittens, little kids are cute, but they grow up to be dogs and cats and teenagers and their not so cute anymore and they bark and meow and yell a lot louder. Take it from a mom with four teenagers 14, 15, 17, and 19.
On a more Serious note, pray about it. God will answer your prayers and if it was meant to be you and your husband will know.
I have one son (my oldest) and three daughters. For a while I thought maybe I would like a 5th child, a boy to be exact. I talked it over with my husband and he felt like he just couldn't handle anymore kids. We prayed about it and I felt okay either way so I let my husband decide. God has given me four healthy children and wonderfully supportive husband, I have no regrets about not having another child.
And although I joked in the beginning about teenagers, on a more serious note. . . I have really good teenagers, they are all active in church, school and after school activities. They don't drink, smoke, do drugs or get into any trouble, but they are much more difficult than little ones!!!! They are strong willed, talk back, yell at you and generally give you a hard time all the time. I'm 45 years old doing this and find it difficult. I have a friend who is ten years older than me raising three teenagers. Ten years makes a huge difference!! It's the difference between being periomenapausal and menapausal. She has hot flashes, very emotional, explosive and exhausted most of the time.
We love our kids and the one thing we both agree on is that it would be so much more difficult to do this alone without a husband. Children strain a relationship when they are young and even more so when they are teenagers. So, respecting your husbands feelings is really important. It may make all the difference in the long run. The kids will eventually grow up and leave home and hopefully you will still have a loving husband by your side when they do.
Hope this helps a little and good luck with your decision.