I need some womens opinions??

all right i was dating this girl in a very serious relationship and while in it she left me 3 times for her ex and then ended it to date some one else now that i started dating agin she says that she realizes that she made a mistake and wants to get back to gether and she says that she wants it to be for ever and i have very strong fealing for her but i think i need to explore my options so what should i do give her a fifth chance or take a chance and date and maybe wind up alone?????