This is not an absolute rule. My bhabi demanded a divorce from my elder brother a year after they had twins after 7 years of marriage.
Your second point about them standing side by side with kids is a different issue which does not necessitate them being together married.
Having kids does not guarantee that the marriage will improve, but it certainly makes a considerable difference.
However, if you are certain that your marriage will not work and divorce is the only option, you should definitely not have kids because they will suffer the most because of the divorce.
Again, going by your one-sided presentation, it appears that your brother got played by your bhabi.
It sounds far-fetched that she was in a happy marriage for 7 years and suddenly decided to walk away after having babies, so it seems that she knew the marriage was doomed but she didn’t want him to get away with no responsibilities, so she talked him into having kids.
But more importantly, here is another thought. Your brother got divorced, your sister has reached breaking point and thinks divorce is the right option after 2-3 months, your deranged views on marriage are well-documented and your father is ready to pull the plug on his daughter’s marriage without encouraging and motivating her to work at her marriage and not give up after 2-3 months.
Now you will obviously say that like your sister, your brother was 100% faultless and it was all your evil bhabi’s fault. It is already obvious with the way you framed the sentence
”my bhabi demanded a divorce”.
I think you and your family need to engage in some serious introspection. What is it that always seems to get between your siblings and happy marriages?
If you get divorced once, you are probably unlucky. If you get divorced twice, you are probably incapable of sustaining a relationship. Similarly, if all (most) of your siblings are in unhappy marriages, then it seems like a family issue.
The introspection has to start with your father. I am sure he is loving and kind, but it is also important to show tough love at times.
His elder son got a divorce, his daughter is ready to give up after 3 months and the third one (you) is in his 30s with the maturity of someone who just hit puberty, cannot control his urges and wants a trophy wife. The first thing he said about his potential wife is that she looks like a tv star.
I think he needs to stand up and put his petulant and entitled children in their place, although I have to say it with regret that it is probably too late now, and that ship has sailed.
Again, I must reiterate that your mother is the only one in your family who is thinking straight, but she is being vetoed out by the foolhardiness and the immaturity of those around her.