I can see that if both are ministers in different churches, it is unavoidable for them to attend different churches. In this case, the wife is not a minister in any church, she just doesn't care for the church her husband pastors and prefers the church she goes to. There would be nothing stopping her from going to the husband's church, she says she just doesn't like the church (meaning the people, the building and the ministries). When we do see her, she's quite stand-offish with most of the members, but will talk for brief periods with some of the women her own age.
And although my parents were of different denominations, they always went to the same church together, they never split up on sundays. As long as my mom lived, my dad went to her church, but after she died, he went back to his original church.