I have been friends with both the man and the woman in the former relationship. I knew them independently. They were together about five years.
For many many reasons, the writing was on the wall that they wouldn't last as a couple. The boyfriend has numerous opportunities to change behaviour/improve but he just wouldn't. He is such a lovely lovely guy but so timid and likely depressed.
The girlfriend is gregarious and very outgoing with a real zest for life. Her (ex) boyfriend was getting her down and she didn't see a long term future with him.
She asked me what she should do. I said if I were her, I think it would be kindest for both of you if you ended things so that you can find someone better suited. She agreed and said she needed to hear it from someone else too as she knew it would destroy him.
The boyfriend is now taking it very very badly and I feel awful that I played a role in it. Almost feel like I betrayed him, even though the relationship was doomed.