I'm going to offer a slightly different idea. You say that you fell into this because you were vulnerable and felt you needed someone to take care of you. What is interesting from what you have told us, is that over time you actually made yourself more vulnerable rather than less. Giving up uni, then a job and finally opting for joint finances. So the more looked after you are, the more looked after you needed to be.
So, I would guess from this that at the moment you are not working from a place of great emotional strength and security. You seem to think no one else will want you, and this seems to be important to you. So I don't think that ending your marriage right here and now will actually help you, it isn't the cure to the condition. If you become more vulnerable to loneliness, isolation, lack of money you are just as apt to fall into a similar trap. If you believe no one will want you you may even replace a boring good man for one a whole lot worse.
What you need to do is start to reclaim little by little your independence. He doesn't sound like a bad man. Would he support you to find a job, be happy for you to have a saving account, or even find part time work and restart uni part time? Or start a small business?
When you do leave, and you will, you need to do this from a place of strength and know that you can cope and won't fall into a similar situation. Plus in a couple of years time your little girl will have been able to develop a good relationship with her father that lays the foundation for a future of shared co-parenting.
However if you really are so very miserable and we don't have the full picture and this man is not as you have described then by all means run.
I sat out 10 years for my own reasons, for my children, financial reasons, and I'm older than you. But life is by no means over and now I am able to make the right decisions and move on in my life. You are very young, but as you have discovered family life, marriage, and having children is not a ball, it is bloody hard work and there are often more sacrifices than fun. That will be the case whether you sit tight with his support or go it alone.