Is it normal to dream about...

so, i've been having these dreams about having sex with my ex-boyfriend. i'm married to the love of my life, but our sex life is a little lacking (we have busy work schedules, and we also have a seven month old baby). i keep having these sex dreams about my ex-boyfriend. they're not reoccurring, they're new & different every time. it's driving me up the wall. is this normal?