Baby mumma drama

aleana
So i have been seeing my man for 3 years but we had a break for 7-8 months because we lived 9 hours away from one another. 
In that time he had a one night stand ( no im not angry about it) but anyway we shortly got back together a while after that. Then in may last year he gets phone call, she had just given birth to his child!! I was shattered and angry at that but it wasn't his sons fault. Every time we go to see abel ( their son) she has some innapropriate comments, first it was a message stating she was in love with him, then it turned into her saying she had a dream that she had my husbands second child, and the last comment/ message was just a week and half ago, she had asked him then asked me if she could use my husband as a sperm doner for her to have ANOTHER child!!! I snapped i told her it was innapropriate ext, 
But for 6 months now my hubby and i had been ttc our own baby, and after she had asked that my hubby and i got into a massive argument and now, he doesnt want another child for an extremely long time he said he would re asses his decision in 2-4 years. 
I am so angry and so hurt i dont hate my step son but i hate that his mother is someone so aggravating and rude. 
Every innapropriate comment she says or messages i just feel like giving up.