A husband is called to serve his wife with the same care as Christ serves the Church. As Christ died for the Church husbands are called to be willing to die for their wives. (Wives are equally called to serve their husbands as the Church serves Christ; so, it’s not like we got off easy here!)
Your husband’s continued inappropriate contact with women is selfish and not at all in line with the covenant of marriage. It is completely inappropriate and it is reasonable to feel distrustful.
I had a similar “line in the sand moment” as @exiled1: I had a knee to knee conversation with my husband that, as I had been explicitly clear prior to marriage that pornography was in no way something I would allow within marriage, and that he had willingly agreed with me, that he had not fulfilled the means test for a consenting and valid marriage and I was within my rights to ask for an annulment.
Honestly, I have no idea if the above is true. I thought it true at the time and it scared my husband enough that he truly saw, really saw, what was at risk because of his behavior. He has become more aware of the damage he has caused to himself and his family as we grow in faith and repair our relationship. (To be fair I have also taken responsibility for my own ungodly behaviors and am working with equal fervor to remove the logs from my own eyes).
Your marriage doesn’t have to end here; but, it is going to take a lot of work and more heartache to get to a point where you have the marriage God wants for you. Are you willing to do that? Is he?
I can tell you it’s worth it. I loved and respected my husband before; but, this experience has taught us both that there is a deeper love, respect, and spirituality available and it is more than we could have ever imagined.
One other note, his behavior has nothing to do with you. As women we have the tendency to validate our worth from the cues of others. It is not much of a leap for a wife to feel like there must be something wrong with her for her husband to view porn. Pornography is not about you. When he commits adulterous acts he isn’t thinking how this may hurt you. He is focused on himself. It is an act of complete selfishness.