Most importantly, what not to do is to arrange dismantling. You can't run to her house and raise the ears of the whole staircase. The neighbors in this case, it will be on her side, and you will look ridiculous. And the husband, of course, finds out about this your deed, and it is not in your favor. After all, men created so that they can not completely break the ties that they had with former wife, especially if that family was a child.
If she pulls your beloved, your calls and texts constantly requires assistance in raising the child, then try to start to talk to her. Explain that once he left her, so she was not happy, and you can't turn back. Instead of spending time on her ex-husband, maybe she's better to look for your new happiness.
Tell me that you are not against dialogue of the husband with their child. Even, on the contrary, suggest that she let him take his son for the weekend. You will see that the child was fed on time and have a good time. And she maybe it's time to give yourself. Maybe she'll try to arrange their own destiny. And then you will be grateful.
If she goes to such concessions, with time you may even become her friends. This will allow you to control the relationship of your husband with your ex, you will always be aware of their meetings. Perhaps in the future you along with your beloved will pick up a child, not to leave him alone with his first wife.
If contact cannot be established, do not show the man that you are having feelings about his communication with the former. Let him give the impression that you do not attach importance to these meetings because I trust him and believe in his love for you. This will further elevate you in his eyes and forced a new look at relations with the former. Unobtrusive ask, how was the meeting with the child, not do something to help, tell me what to buy on a future visit.
And the surest way to ward off the former is to give birth to their child. Then the husband will switch all the attention on the new family will be around to help you and he has no extra time to on demand rush in the first family. And the ex-wife will understand that you have formed a family relationship and she has nothing to return. And leave you alone.