Lucky it's only been a year.
Nothing wrong with being a career orientated person and I'm sorry for the loss of your Father and your health issues.
I'd also be wary of any "mate" telling you that your man is cheating. In my days, that only meant that "he" the mate wanted to get into your pants and then brag about it to his so called friend, whom for what ever reason, he's not really close to as a "friend".
If he prefers constant communication, someone there, yes dear, no love, get me a coffee, then that's his make-up . Doesn't matter that she doesn't work, that she's not you. Obviously your career and assertiveness is not something he can cope with.
Obviously, she wasn't enough for him either if he cheats.
Karma has a way of getting people back. Why go back to her when it's over and spill beans yourself?
Is that really going to make you feel better?
Leave it, leave him, move on, focus on healing, focus on your career and be more attentive next time you decide to date someone, that you are dating the right "type" that will suit you and your life and his.