I think it might be wise to go for a hypothetical "if the worst happened, where would I stand..." appointment with a solicitor who is a specialist in family matters.
I am not suggesting starting divorce proceeding at all. It's just that this aspect is hard to manage if you do get a body slam later down the line, people do tend to has misconceptions about their rights and the financial implications and often the person who created the strife has a head start in terms of creates themselves an advantage legally speaking by being able to anticipate the need for legal input.
You know how you go to your doctor for an occasional check up as a preventative measure, or to head off unknown about things before they become very difficult to manage, well think of this as the legal equivalent. Sitting at home worrying about a constant ache is far far worse and far far more painful than finding out what your treatment options are if it does turn out to be as bad as you think it might.
At a time like this there is so much that is beyond your control, so much information potentially withheld from you. If nothing else exercising your control to become informed as to where you stand in the worst case scenario, will reduce the sense of all things spiraling and leaving you feeling powerless and entirely at the mercy of others peoples yet to made choices. that gives you a strength that could make all the difference in how you react to provocations or attempts to manipulate you when you are down.
If at a later point it appears he is anticipating a "cake and eat it" situation, letting him know that you have sought legal advice may be a tool that can be used to clarify in his mind that the autonomy in this situation is not his alone, and that he is taking greater risks with your relationship than perhaps he imagined.
My advice, if you are not ready to tackle him about the texts just yet, is to take care of creating a sense of control for yourself, vaccinating yourself against being left at a disadvantage thanks to an information gap and then seeing if that has bolstered you enough to feel up to challeneging his behavoir.
It's just a check up, you don't have to fear it or feel you are deciding your destiny. This is something for you, about you, at a moment when you feel like the last of anybody's considerations.
((big fat hug)))), I am so very sorry you are having to deal with this.