Though the paddhathis may vary slightly according to the school they follow, Kalyanotsavams in Bhajan Padhathi are being performed by many a bhagavathas. Meenakshi Sundareswarar Kalyanam (ancient), Valli Kalyanam, Seetha Kalyanam, Rukmini Kalyaanam are the ones that were performed in ancient days. Now-a-days, Ganapathi Kalyanam, Dharma Shaatha Kalyanam (wrongly called Ayyappa Kalyanam) are being celebrated. These were added by present day bhagavathas and were not prevalent in ancient times. Radha Kalyanam is being performed widely, though there is an argument that it is Gandharva Vivaham and no marriage took place between Radha and Krishna. The argument is that Radha was a Gopi and Krishna did not marry a Gopi. All Gopis considered Krishna as their husband and Krishna never married any of them. Krishna married only Rukmini and Sathyabhama. Sathyabhama Kalyanam is not being held probably because she was a Deva Kanyaka and not a Bhaktha like Rukmini, who longed for Krishna and then got married through her divine love. Radha Kalyanam is widely accepted and is being conducted any time in a year, whereas Seetha Kalyanham is performed during Ramanavami, Rukmini Kalyanam during Gokulashtami and Meenakshi Sundareswara Kalyanam during Dhanur Maasam.
Here we deal with the padhathi , meaning, philosophical essence, importance, significance of Radha Kalyanam. While the other Kalyanams were described in various puranaas, Radha Kalyanam is not described in any Puranam except Brahma Vaivartha Puranam, which describes the scene in Golokam, which is said to be placed above Satya Lokam. Here Lord Madhava and Radha exist as the Purusha and Sakthi in original status (not in any specific physical existence). This existence is said to be the total blissful state, which is explained as the status of Brahman. This Brahma Swaroopam (because they are together and not separate) is playing into the world in the form of Krishna and Radha. For this there is a story stated in the Brahma Vaivartha Puranam.
Once when a bhaktha was discussing various aspects of bhakthi, existence, birth and death with Madhava, Radha got upset and cursed the bhaktha. The bhaktha got enraged and cursed Radha devi thus: You got upset like a human being, may you go to the world and take birth as a human being. When Radha realised her mistake, she felt aggrieved for she cannot stand separation from Lord Madhava and asked for ‘sapa vimochanam'. Lord Madhava consoled her, saying that he would take birth as Krishna to Devaki and Vasudeva and would be reared up by Yasoda and Nandagopa in Brindavan and she can take birth in Brindavan and enjoy his presence always as a maid to Krishna. She took birth (before the incarnation of Krishna) as the child of Maharaja and came to Brindavan and took care of the child Krishna as a Gopi.
A question arises that if she took birth in the world before Krishna, she must be elder to him. Yes, as Radha and Krishna but not as Madhava and Radha. It is like in a drama you act like a young boy. Do you lose your age? It is only for the play. Secondly, it is not Radha Krishna Kalyanam, but Radha Madhava Kalyanam, about which we will discuss further and hence the age does not come in the way. Radha has lost memories of her original status/existence whilst Krishna always was in the knowledge of his original existence as Madhava because he is an incarnation. So much for the preface.