I dated a girl like this. Absolutely avoid. I couldn't quite figure her out until I stumbled upon narcisstic personality disorder (npd). Not saying yours has this but the signs are that it's possible.
Basically everything is about her. Ask yourself if she has any empathy. Is there any reciprocity? Does she even care about you? Does she ever admit she's at fault? A woman like this is an emotional vampire and will suck you dry.
NPDs can be VERY charming, manipulative, and know exactly what hooks to use to pull you back in. They can and will take advantage of people's caring nature. That is why you're still attracted to this one when you should be running fast in the other direction.
If she is npd, she will never love you. She will cheat on you when she finds somebody better. (Her cheating is not her fault. She deserves better than you. You don't make enough money. Give her enough attention. No matter what you do it will never be enough.)
The marriage she wants isn't about both of you. It's about her alone. She feels she deserves one and possibly sees you as tge chump to give it to her.
Also, a good woman (or man) never ever badmouths their spouse to anybody else. Instead they defend that person tooth and nail. HUGE red flag. What's it going to be like when you're actually married?
Avoid this one. She's using you because you're nice and she can walk all over you. She doesn't respect you.