Also OP, some after-thoughts, if your wife is not feeling aroused enough during attempted sex, then the issue is you, not her. Remember, she is the blank slate, meaning she does not have any aversions or dislikes for any particular sex act; likewise she doesn't not have any preferences. She doesn't know what she is missing out on. It is your job, as the experienced partner, and as the husband, to teach her what is enjoyable.
I say this from experience with a complete virgin a couple years ago, and also numerous anal virgins that I've been lucky enough to break. First couple times for sex were not enjoyable for either of us. I had to stop and realize that she didn't yet know what is enjoyable and I had the opportunity to teach her the things I liked. It's just like introducing someone to anal. If you are extremely rough and cause pain the first time; they won't want to ever do it again. However, if you focus on them, ensure they are well lubed, and they orgasm from it...they'll want to do it everytime. By the time I was done with my virgin; she was submissive in every facet of the word when it came to sex. I invested extra time on her enjoyment every time I introduced a new position, or hole, or toy. But after that initial investment; it was all about me. Sex with her, and the anal virgins, became some of the most arousing for me; not one because everything they did was geared towards my direct preferences since that's all they knew, but knowing they owed all their sexual experience and joy to me was intoxicating. GL OP, again, this sounds more like a mental hurdle that only you need to overcome.