There are a lot of Bollywood films that show the dating and courting stages of relationships, but only a handful talk about marriage, and that too in the most realistic way possible.
Ones that talk about what follows post the grand wedding, the part where it's all about the relationship, and how two people function together.
This 2000s fav. showed us Vivek Oberoi and Rani Mukerji playing a young and slightly naive couple who elope and get married. But they're forced to grow up as they learn to co-exist with one another in spite of their personality differences. You can watch it on ZEE5.
2. Tumhaari Sulu
Tumhaari Sulu shows Sulu's (played by Vidya Balan) and Ashok's (played by Manav Kaul) marriage amidst a time Sulu is offered an exciting job as an RJ. How the couple manages to share responsibilities so that Sulu's career can take the front seat is what is interesting to watch. Catch this on Amazon Prime Video.
3. Shaadi Ke Side Effects
This romantic comedy is about Sid (Farhan Akhtar) and Trisha (Vidya Balan) who although, are very much in love with one another, are just another young couple trying to figure out marriage. Somewhere in the middle, Sid starts to feel like a terrible husband and father and has his own personal journey to get through before he begins to appreciate his family. You can watch the film on Hotstar + Disney.
4. Chalte Chalte
Chalte Chalte was kind of ahead of its time back when it released (much like Saathiya, actually). It showed the audience a story of two people, Raj and Priya, who fall madly in love and decide to get married. But the differences in their family backgrounds and upbringing ends up causing a brief rift between the two, ultimately leading them to understand each other better. It is available to watch on Netflix.
This is one of those films that shaped both Amitabh Bachchan and Jaya Bachchan's careers greatly. Abhimaan shows the audience a story of Subir and Uma, and how the two end up drifting apart (only temporarily) because of Subir's insecurities as Uma turns into a greater, better-known singer than him. You can watch it on Amazon Prime Video.
6. Akele Hum Akele Tum
Another film that shows marriage isn't always a straight road up to that old and grey sort of love. Akele Hum Akele Tum is a film that shows two professional singers, Rohit and Kiran fall in love, but also separate pretty soon as Kiran chooses to pursue her ambition and leave Rohit. Ultimately though after many years of living apart, the two fall back together post a tumultuous custody battle for their son. It's available to watch on YouTube.
7. Main, Meri Patni Aur Woh
A film showing Rajpal Yadav's supremacy, Main, Meri Patni Aur Woh is centred around a marriage between Mithilesh and Veena and how Mithilesh learns to overcome his constant insecurity of not feeling good enough for his wife. You can watch the film on Netflix.
8. Dum Laga Ke Haisha
I may be wrong, but don't we all love this film? Dum Laga Ke Haisha, shows us a tale of two married folks. Where Prem is initially shown to be judgemental of Sandhya's weight but with time, and of course some obstacles, learns to understand her on a deeper level. Causing the two to finally be on the same page and ready to dive into their marriage. Catch the film on Amazon Prime Video.
9. Just Married
Just Married shows the audience a couple who finds themselves in an arranged marriage and looking to get past the initial awkwardness of the relationship. You can watch it on Amazon Prime Video.
10. Meenakshi Sundereshwar
Meenakshi Sundereshwar is an adorable story about a couple who spends the first year of their marriage trying to navigate a long-distance relationship. It's a modern-day, arranged marriage plus a long-distance plot that stars Sanya Malhotra and Abhimanyu Dassani. You can watch it on Netflix.
Maybe these would be a good watch before you seriously start considering marriage.