Hi,

I just read this whole thread,

I fully understand you, for the first few years after my wedding I had the same issue. The interesting part is that we are so not a match, she is the bossy type of lady that I would never want as a wife. so why was I even thinking about this. DONT KNOW!!! The only thing she had is that she is skinny and my wife is not so skinny.....

But BH the last few years I don't care about her anymore.. I think the reason is that I don't care anymore BH for skinny ladies... I have no craving for that. I don't see the point. What will I have if my wife is skinny.. (the only thing that other men would look at her on the streets and be jealous, I don't need other men to like her.)

Have a great day guys!!!

I noticed that on the Halacha Headlines podcast this week, they spoke about how to deal with a new sister in law. Ironic. I wonder what they said

I actually listened to it today, rabbi leff said that relationships with sister in laws are dependent on the mimhag of social norms. Example.. some places are very formal and don't speak to eachother some speak more. U can call by first name if thats what people do
just don't cross any red lines

Problem is in regular balabatish/yeshivish circles the problems are a lot more subtle- sitting on the same couch not right next to each other- having a conversation about hashkafa at the kitchen table without anyone else- sharing a joke- commenting on a haircut or new suit- things that may not be be'etzem problems- but if they are problems for someone they are problems

Very interesting thread... I read through the whole thing. If I were in such a situation I would speak to my Rav and my sponsor first of all, as it sounds quite complicated. I found my Rav very helpful in this situation, I am very close to my Rav as I would speak to him every week for an hour for an entire year. So I recommend either finding a Rav who you feel comfortable opening up with or reviving an old trustworthy relationship, you might find an incredible answer. We only have written information but a conversation will give more information, it is more dynamic and interactive. It has changed my life for the better, it might just change yours. If you would like to discuss the situation with a friend I am open to speak I can give you my number. But I don't have any experience in this area. Someone who is married will be better. 
TBH I doubt this relationship will get sexual. The issue sounds more obsessive which I definitely can relate to. The frequent interaction and the deep conversation. I would feel very much curious in such a circumstance as I have done on other occasions. This is especially difficult to avoid as you are in close vicinity. 
First thing I would do is daaven for her and her husband.
I wonder if talking to her husband is an option, I wonder what you can say without hurting him. I wonder if he has a low self esteem. I can only see this whole thing being quite hurtful towards him. Maybe if she asks you a deep question you can call her aside and say to her why don't you ask you husband that question? Go on to say a maalah or two about him. That way you are helping their relationship, he feels better about himself and she has built a deeper relationship with him? This is without knowing the situation, the people, the dynamic. finding a way to build HIS self esteem is, I think the key to all this.