What does it mean practically that every kesuba has strife?

Question

The Gemara Shabbos (130a) says

וְכׇל מִצְוָה שֶׁקִּבְּלוּ עֲלֵיהֶם בִּקְטָטָה, כְּגוֹן עֲרָיוֹת, דִּכְתִיב: ״וַיִּשְׁמַע מֹשֶׁה אֶת הָעָם בּוֹכֶה לְמִשְׁפְּחוֹתָיו״, עַל עִסְקֵי מִשְׁפְּחוֹתָיו — עֲדַיִין עוֹשִׂין אוֹתָהּ בִּקְטָטָה, דְּלֵיכָּא כְּתוּבָּה דְּלָא רָמוּ בַּהּ תִּיגְרָא

And every mitzva that the Jews initially accepted upon themselves with contentiousness, such as the prohibition against incestuous relations, “And Moses heard the people weeping, family by family” - They wept over matters pertaining to their families, as they were prohibited at that time from marrying family members, they still perform with contentiousness. The fact is that there is no marriage contract and wedding in which contentiousness does not arise, as there is inevitably some conflict between the parties.

What does this "contentiousness" mean practically speaking when two families and their children come together peacefully to the chuppah with no conflict?

Answer 1

Tosfos in Kesubos(2a says):

ליום הרביעי - ולא בליל חמישי כדאמר בפרק בתרא דנדה (דף סה:) דליכא כתובה דלא רמו בה תיגרא כ"ש אם יעשה נשואין בליל ה' דאיכא למיחש שיטרד בנשואין וכתובה ולא יבעול:

And the sefaria translation accurately explains the tosfos, as was explained by my rebbi in yeshiva when we learned this gemara: (the translation was "Merged from 'Tosafot, Translated by Jan Buckler', 'Tosafot, Translated by Jan Buckler.', and 'Sefaria Community Translation'":

On Wednesday. In the secular calendar Wednesday night is the period that begins after the period of daytime on Wednesday. The Torah does not have names for the days of the week. They are referred to by number, first, second etc. In B’raishis 1, 5, the Torah says: and there was night and there was day, the first day. This teaches us that in the Torah calendar night precedes day. What is referred to as Wednesday night in the secular calendar is caller the fifth night in the Torah calendar.Our Mishna says that a vbetulah is married on the fourth day. Tosfos comments: But not on the fifth night (Wednesday night), as the Gemara says in Needoh (65b), there is no marriage contract where there is no dispute about the terms of the agreement and time is always needed to settle the disputes.1Nowadays we use a standard marriage contract for all. During the period of the Mishna each marriage contract was negotiated individually. All contained the minimal requirements of the sages, but there was much more to be negotiated. This could have drawn out for a very long period and by the time it was over, the couple may not have time to consummate the marriage that night.Certainly, if the marriage is made on the fifth night, one needs to be concerned that one will be involved with the terms of the marriage and the contract and he may not have relations with his bride during that night. He may postpone his relations with her till the next night and will first be able to present his claim of lack of virginity on the following Monday. By that time his anger may have cooled and he may not complain to the court at all. It is imperative that the marriage take place Wednesday afternoon, so that he will definitely have relations with his bride that evening and if she is found not to be a virgin, he will still be angry when the court is in session Thursday morning.

I did not look into where this explanation comes from, but I'd assume that if two people explained it the same exact way, it probably came from somewhere.

Answer 2

The gemara is comparing things like bris milah (a mitzvah accepted with simcha) to things like marriage (where the relevant mitzvos were not accepted happily). Perhaps we forget how remarkable it is that our holy nation is able to do a bris milah with joy. Someone might easily recoil and say, What! - how is it possible to do that to a helpless baby?! We didn't say that. From our very beginnings we turned away from our feelings and joyously did the will of our Creator to bring our sons into their covenant with G-d. It is almost as if we turned off that part of our yetzer hara; it no longer even seems difficult to us.
Marriage was different. When we were given the laws of arayos, instead of saying, Our purpose in getting marriage is to create families to serve our Creator, so of course we don't want to be married to someone when our Creator says no. No problem!
We didn't do that. We were בוכה למשפחותיו (Bamidbar 11:10), "crying about their [forbidden] families". Our purpose in getting married was still our own desires, not Hashem's desires, and we were unhappy when the new mitzvos told us to do differently. As a result, marriages are hard to do, since all the families and people involved have their own desires which will never completely align.
I guess it didn't have to be that way. It could have been that we gave away that part of our yetzer hara with joy as we did with bris milah. Marriage would have been a way of serving G-d through our families. Why would we quarrel? It's not about us! Let's all work it out together to make sure that the resulting new family is best prepared to build a bais neeman b'yisrael.
Boruch Hashem, many couples and their families do have exactly that attitude. It doesn't take away all the stress and issues with shidduchim, but it surely helps.