Why would an ex-wife come to tell you that she's pregnant knowing there is nothing between us?

I was married to her for eighteen years and was the only one who professed love and security.she's not yet legally divorsed with me and has had a few lovers,my baggage has been tossed out now for a few months,I dont want her back,I'm just moving on with my life and finding hapiness and direction again.I m not even in a rush to find relationships.intelligent women need only reply.