Am I wrong to feel like I need to cheat on my girlfriend?

My girlfriend and I been butting heads lately and I know she is suffering mental illness menopause etc, Like a flip of a switch she started changing on me the intimacy and affection died down , I feel like her walking punching bag she points her finger at me and criticizes me and belittles me My feelings of concern don’t matter to her she always turns it around that I am this horrible person that I am trying to control her when that isn’t the case at all , I just know she isn’t respecting me like I do her , I have told her I want to break up because things aren’t good between us but she won’t leave , I feel like she is stringing me along until something better comes , I have had talks and talks with her to the point she doesn’t remember half the shit we talked about and she doesn’t remember shit she says to me that is vicious shit, I have told her to leave if she isn’t happy with me anymore , I will walk away from her and then she will come chasing me back when we make up we will have amazing sex and then she will say it’s just sex don’t think everything is fine between us leaving me dumbfounded as to why are you giving me sex if you aren’t in love with me? , So I think to myself she must be a whore , and that she is leaving her options open, I have constant question marks over my head to the point I don’t think I can tolerate this abuse anymore, I am feeling lonely and want to be wanted , to the point a big part of me is open to meeting someone else , Am I wrong to be open to meeting someone else?
Am I wrong to feel like I need to cheat on my girlfriend?
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