Ummm… the Church isn’t telling him that he can’t have sex with his wife… you aren’t technically his wife. You are the woman with whom he has entered a civil contract, but you aren’t his “wife” by definition. In order to be married, you have to fulfill God’s natural laws, the laws of the state and the laws of the Church. You have only fulfilled two of the three and therefore you are objectively not married.
It’s like this… a man and a woman decide that they want to be married, so they go out into a field and exchange vows and from then on present themselves as married (think the scene in the movie
Braveheart where the Mel Gibson character and his woman go off into the woods and exchange vows and consider themselves married). So, they live together as husband and wife and even have children together. But, after a couple of years, she’s tired of his **** and she decides that she wants to go and get a divorce. So, she goes to the judge and files for a divorce. What is the judge going to tell her? He’s going to tell her that he cannot grant her a divorce because she’s not married. She may have thought she was married, subjectively, because they exchanged vows and lived as married, but they did not go and get a license or stand before the civil official, therefore, they do not have what is defined as a “marriage” therefore there cannot be a civil divorce.
It’s the same way in the Church. If you don’t do what is required of you, you aren’t objectively married. You can think you are married all you want. It’s not a matter of the subjective. I can subjectively think that I’m a man, but the objective reality is that I’m not. Just because you think it’s true, doesn’t make it so. Marriage is an objective reality, not a subjective one.
So, back to my original point… the Church isn’t telling him that he cannot have sex with his wife. If you were, in fact, his wife, the Church would be telling him to have as much sex with you as he wanted! All day long if he wanted to!

But, you aren’t his wife in the objective reality sense.
Ultimately, it looks like you’ve made your decision. It’s hard to live according to Church teaching. No one said it would be easy. But, everyone has to set their own priorities. You have to decide what is more important to you… the here and now or the hereafter.