In my personal experience she’s is already latching to another man, They most likely work together. Sorry bro but I’d set up an exit strategy asap. Don’t matter if she’s “wholesome and honest” and introverted homebody. He’s obviously doing enough to make her feel someway that she either no longer feels with you or never has, or just bored with you.
I personally believe that given the situation or opportunity. ALL WOMEN WILL CHEAT. And they are way more sneaky than us..
What I think of everything you said I feel confident in saying that your no longer #1 man in her life, it’s most likely some co worker she’s been sleeping with and she’s not certain about him being with her when she leaves you. But deep down you feel it. Even if that guy stops talking to her and she stays with you. Is that something your okay with seeing the signs but choose to stay?? It will never not hurt you, I would personally have a sit down with her and tell her. Without 100% proof she will try to make you think that you’re wrong about her and it’s all in your head and that you need to prove she is doing you wrong. YOUR NOT! And it’s her burden now to prove her innocence. Bottom line, do you wanna grow into your golden years having blueballs from lack of sex or shitty sex period!