There is no way the womb from Ishu can be planted in Shagun. Adi going back to Shagun is a possibility. Adis life as been with Shagun all along. Besides he sees the change in her. Though he is with Ishu and Raman, he still misses her. Either he will go on his own will, ior now that his ishima is pregnant, just to reduce her stress, he might go tonshagun. It can also be a realization track for Raman, no matter what Audi will always choose Shagun. Audi loves ishima to he may do it just to protect her. As a tween he can understand the situation much better. Hope I made sense.