I know this will be a revelation to someone. When you’re in a relationship there’s usually someone else involved. That’s why it’s called a ‘relationship.’ So if you’re unhappy in that relationship, chances are the other person is too.
This is where some will make devastatingly selfish decisions. In a misguided attempt at justifying their happiness they have affairs. It’s the “I deserve to be happy” justification. But what about the other person in your relationship? Do they deserve to be happy? Do they deserve to be respected? Do they deserve the truth?
And you! What you deserve is to preserve your self respect.
You do that by doing the hard thing, not the chickenshit thing.