Either together in the back seat, or the wife in the front with the friend and the husband in the back.
The ex husband should come alone (without his girlfriend or second wife) and sit on the side of his ex wife's family. If you have a girlfriend or you're remarried it would be in poor taste to bring your mate to your ex wife's funeral.
Traditionally, a wife sits on the left side of her husband because it is believed that the heart is located on the left side of the body. By sitting on the left, the wife is symbolically closer to her husband's heart, representing love and closeness in their relationship.
There isn't any real etiquette for seating arrangements in a car. The husband and wife can sit together with the husband's buddy in back seat with the children or, the husband and his buddy can sit in the front seat with the wife and children in the back seat.Usually the adults sit in the front seat and the children in the back. If your husband has a buddy with him, he should sit in the back too. The wife doesn't become a child just because the husband's buddy is with him.
The answer depends on what's written in your governing documents. As well, if the husband and wife own the same condominium unit, voting is problematic, since usually only one vote per 'door' is permitted. This may complicate board votes if both are trustees -- board members -- of the association. Best practices would dictate that one or the other sit on the board -- act as a trustee -- at a time.
It depends what the situation is and if they are good friends with you and your husband and you are joking, but it's best not to sit on other men's laps as it could cause jealousy by the wife or a misunderstanding.
Because your husband did not divorce his first wife then you are not legally married. There is a Statute of Limitations in difference States and if you have been married for several years then most likely the marriage would be void. However, you need to sit down with your husband and tell him he because he did not get a legal divorce he needs to look into it and if he is does not then you are not staying with him the way things are.
To sit there and look pretty.
If your husband is spending more time with his friends wife than he is with you then it is highly possible he could be attracted to her. It is also possible they may just be friends as he is with her husband so don't jump the gun yet. It is very important that husband and wife have good communication skills and since you are suspicious and curious as to whether he finds his friends wife attractive then you should sit down with him and express your feelings about it. Be wise and also realize that your husband finds you attractive and still loves you, but it is normal that even a husband can find in a group of your friends a woman that is attractive and as long as it's 'look and don't touch' then everything is fine.
they dont sit
Assuming that the driver is the husband, there is no exception to the rule that the husband must respect his wife at all times and as such, I would have the wife sit in front beside her husband and have the mother-in law seated in the back seat. I also believe that the mother-in-law would agree and be pleased that her son-in-law is treating her daughter with respect. However, I'm speaking as a north American and may not be aware of customs in other cultures regarding this particular situation.
* There is no standard etiquette for normal passenger seating in a car. There is nothing wrong with you getting in the back seat if another male is driving with you and your husband. Sometimes older people have a difficult time getting out of the car and the front seat is best for them or, perhaps the two men may just want to talk and it's much easier of the two males are in the front. If you and your husband are in the front and pick someone up unless they have a physical handicap then no, just stay in the front seat beside your husband. However, if you are pushed in the back seat for no reason and it bothers you feel free to claim the passenger's seat.