This is a more complex question than what you asked. It's not just about real love or convenience. You seem to make bad choices without thinking twice. First you had 4 kids with an abusive man then you married without love then you met some guy and had his baby right away then went back to your ex-husband.
For some reason I think that if you decide to leave your husband you will find another jerk and have his baby. If you have a job and are able to support yourself and your five children then leave and think about love later.
However, if you're going to abandon your kids or starve them then you should stay with your husband. But he isn't their father anyway and hopefully he doesn't molest them. Make sure that's not the case. It happens to about 30% of children.
You have to take responsibility for your actions. And you have huge responibility - your five children. By jumping from one man to another you won't solve any problem. They all feel that you depend on them completely and soon enough start manipulating you.
Perhaps you could move in with some woman with children and share costs of life with her. You can find her through the associations that help abused women, for example. If you don't work, you should find a job and perhaps think of some additional training that will open some new opportunities for you.
You also need to build your self-confidence and self-respect and not let men treat you like trash. You're only 28 but you need the maturity of a 58-year old in a life situation like yours. Good luck!