I am a student of the
Life Mastery Program and am fairly new at giving advice, but this is what I am sensing--
Your husband says "he thinks" he might have feelings for this woman. This could possibly be a game with him. He knows what he should do. He is not about to give up his family for something that is not a sure thing. I sense that she is not serious about him and there is a probable chance that she does not know that he is married. This is possibly nothing more than a mild flirtation, but it is not an acceptable action for a married man.
It is easier said than done, but if you were to ignore his comments about this other woman and act like you don't care one way or the other, how do you think he would react? Most men do not tell their wives that they have feelings for another woman. This appears to be a game of mind control, which you do not need to be a part of. I know that you love your husband and your son. You must remain strong for the sake of your son, but try to have a "back-up" plan to provide for your son. The chances are more in your favor that your husband will stick around, but he appears to be immature and this is most likely not the last game that he will play.
Please keep in touch and let us know how you are doing.