fantasying about sex with a female

I am 24 weeks pregnant with my 3 child and will be married for 8 years in August. I find myself  fantasizing about being with a women I even have dreams about it and I am very aroused when I wake up. I have never in my life been with a girl and never really thought about it either. Is this a normal thing while being pregnant? Or is my mind playing games or trying to tell me something? I am so confused not sure who I should even being talking to about this.