Learn to be happy single before getting into any relationship. Take time to work on yourself if you need to. Your happiness shouldn't be dependent upon whether or not you're with someone, because being with someone should add to your happiness not be the reason for it.
This is one of the biggest reasons so many stay and suffer in toxic relationships: they stay in the relationship, no matter how toxic it may become, because for them they believe loneliness is just too hard to bear, because they feel they have nothing else to hold onto.
Don't be that person. Be the person who can be happy alone, the person who is not afraid to walk away. You don't need anyone to be happy, much less someone who just mistreats you and doesn't give a crap about you.