Hello, I am Rafael. Thanks for asking your question - I'm here to support you. (Information posted here is not private or confidential but public).
I am sorry to know about how challenging this situation has become for you.
Could you please tell me for how long do you know each other and have been dating?
Which are his reasons to justify such approach, the secrecy about your relationship?
This is a young relationship but also one with real commitment as you said, then how does he justify staying married if he has no plans whatsoever to get back together?
Then he cannot afford divorce, right? For a mature adult to state that he does not get divorce because he does not want to make her wife feel bad is not an acceptable reason at all, it does show anything but seriousness about ending marital life and rebuilding a new one. Then if you are together and he keeps your commitment secret, then it would be another concrete red flag showing serious issues in your relationship.
When you started your relationship 3-4 months ago, didn't you discuss your basic needs and expectations about his marital status, regular sharing and closeness to wife, how public or secret your relationship would be and everything else relevant to the commitment you were creating?
I see, then it makes sense what you say and your fears about his real willingness to move on with his life and invest in this relationship with you. His concrete actions show he is not working on detaching and setting new boundaries between them but he's been perpetuating their relationship and does do things depending on what his wife thinks and feels, to the point he doesn't do things that could lead to arguments or for her to get mad, and that says a lot.
it's tough to be in your shoes and it seems there is not much you could do but to reassess your core needs and expectations about this relationship, being clear about what you are willing to afford, then setting consistent boundaries and taking consistent actions, hoping he would agreed with you and support you, otherwise it would not work, unless one of you radically changes what you expect and need from the other, and such change should not be forced but something you would truly be willing to do affording all the consequences, otherwise you would fuel a dysfunctional relationship that would not evolve into anything healthier or more fulfilling that is is in the present. Tile will tell for sure.
I would evaluate what I want, need and expect from my partner, discuss about it with her in order to find out how well she is able and willing to work with me on building a healthy and fulfilling relationship, where both feel respected, understood, loved, supported, showing in consistent action our mutual commitment. In case we were not able to make of these words-agreements a concrete reality, I would confront any unhealthy or inconsistent behavior in order to work on changes and set new boundaries, then if I see no change and I do not feel like changing myself and adjust to what she wants and does, then I'd have to reflect on moving on and end the relationship.
Nobody but you know how you feel and how tough it is, but it is only through your direct experience that you could learn and find out how truly compatible you are and how well your individual paths and life styles match each other.
As long as you feel it is worthy and something you want to try regardless the limitations, challenges and issues, you could work on it, having an open mind willing to make adjustments and changes in consistency with what you learn in the process, whether it leads you to get closer or away from each other.
You're welcome. Thank you for your trust.