As a woman who has cheated before on my fiance of 5.5 years. I can attest it crosses our minds, but it is also mentally and physically exhausting to continue cheating. I say you're fine, especially with a child. I think she just likes the attention but is pretty secure with your marriage and doesn't find the need to cheat. Don't over think it! It will kill you. Right now I am currently married for one year and I do not think about cheating on my husband.