You really need to have lived it or know someone who has to best appreciate, perhaps.
MC has never been shown to have a strong, directed personality and is highly considerate, even debating himself on giving in to his desires for those who play the "harem" path. As he reflected, Bethany (an A+ personality type, egotistical and highly manipulative) knew how to manipulate him in all their years together and they only split when she said so - even though he's since related how long things were terrible between them.
He has been a session and traveling musician since college years, has a clear history of not standing up for his needs in a relationship and this move to Melody's town appears to be only the start of his trying to establish roots in one place with an independent lifestyle. OF COURSE Bethany can come back and press all those buttons again - it took the help of a close friend (in this case, Melody) to finally help him feel that the tether to her can full and well be broken.
MrDots' team laid the foundation for this stressful event and clear save by Melody that the MC went through - we can't all be rugged individualists in this world. I was actually amazed at the flexibility in responses that they built into the MC for this episode, it was quite well done, IMHO.
Likewise, they managed an even more tenuous and highly emotional event for D and the MC in the latest DMD episode, where her (again, A+ personality type) mother was finally confronted - in that case, the MC had already gone through enough time to learn from and overcome how he and D had been manipulated multiple times over . . . which was not the case for the MC in Melody 0.07.