Baba Basra 113a - Why is a Husband the Primary Inheritor?

The gemara concludes that in a case where leah inherits from her father lavan and then leah dies, her husband Yacov would inherit her. But, if Leah dies before lavan, so that the property of lavan is only considered ra'uy to yacov, then yacov wouldn't inherit, rather reuven who is the son of leah and yacov would inherit. The gemara explains the rationale for this to be that leah's son can inherit from his grandfather lavan through her, but a husband cannot inherit through his deceased wife. Simply, this could have been explained based on the fact that when leah dies, she is no longer married to yacov, so the relationship is completely broken as if they were divorced so that yacov is no longer able to inherit through her. But, the gemara seems to hold that since at the time that leah died she was standing to inherit from lavan, we should consider it as if her inherits the properties that lavan would eventually bequeath to her, already now at the time of her death. Therefore the gemara explains that since the property is only ra'uy to leah at the time of her death, and she didn't yet have it in her possession, yacov cannot inherit if from her.

Tosafos asks, if we allow a son to inherit property that is ra'uy and not a husband, so we see that the son has more power. So, why are we so convinced that the husband inherits before a son, maybe a son should always be first? Tosafos answers that a husband doesn't inherit as a "relative" rather he is called a "she'er", meaning he and his wife are considered one unit, so once we know that he has rights to inherit, he comes first since it is considered as if the property is staying where it was.

However, the Rashbam seems to understand that this is not a strength in a son over a husband because Reuven doesn't inherit ra'uy from his mother, rather reuven inherits from his grandfather. Meaning, at the time Lavan dies, Leah would inherit him b'kever, and pass it on to reuven her son. She wouldn't pass it on to her husband since at that point in time he is no longer her husband (the moment she dies, their relationship is broken). The husband is only entitled to inherit at the time of her death, but has no inheriting rights on things that come to her only after he death (even the hava amina that he would inherit ra'uy, that is because we consider her to have the possessions of lavan in her possession at the time she dies - until we establish that ra'uy isn't in her possession at the time of her death). Therefore, the Rashbam doesn't have to come onto the chiddush of Tosafos that the husband inherits before a son because he is considered one "guf" with her. But, in truth, the rashbam 111b d.h v'ha'ish, offers his own rationale that a husband inherits before the son. He explains that the rationale behind the husband comes first is that he isn't a blood relative at all and therefore shouldn't inherit at all. Yet, the Torah says he does inherit, so it is like a gezeiras hakasuv that he comes before all relatives even a son.