Imagine.
You find yourself dating a person who's burnt our from work, so you support them and marry them.
She then wants to work again and you support her for that too.
She repays you by having most of her dinners with her co-workers, even missing out on your anniversary (the plan was already made, and she chose to cancel it).
Now you're the one having a tough time at your job, your partner instead of supporting you, is continuing the same as above (what's worse is she knows about it too) and
When you have a talk with them like any reasonable person, she chooses that getting divorced is the best solution, sure , for her that is. Well if she could have thought about his feelings then we wouldn't have reached at this point eh.
I think plenty of people here can say with surety that that man isn't ever thinking about having feelings for anyone again.
She realizes that she didn't care for his feelings and didn't support him but does she really? The author included this to have the FL misunderstand and also give some wise advice from the side chara but do they also understand the reality of life. More than half of men aren't getting back up from that.
Hopefully we see him again doing well without her and hopefully we don't see her romance, really not looking forward to it.