It is a really good idea to check out different meetings. While many alanon meetings tend to have alot of 'wives of', this is not true of all. You have to shop around a bit. You can also ask attendees at one meeting about others in the area. It is amazing how much some alanoner's know about other local meetings (who attends, age range, format, how comfortable the chairs are, lighting, books available).
If an ACOA meeting is centered on the 12 steps, it will likely have a big spirituality component. A fundamental part of any 12 step program is putting a higher power in charge, and prayer/meditation is really part of that process. But no one should be trying to convert you or force you to say any particular prayer. It should not matter to anyone in an alanon meeting what your concept of a higher power is (Goddess, gods, trees, rocks, extra-terrestrials, all of the above). Check out the postings for Step 2 in the 12-step studies on this forum, and you will see that even atheists use the 12 steps.
Don't be put off by a disappointing meeting. Many years back when I finally got the courage to attend an alanon meeting in my city, I called a phone number, got some locations and times (this was pre-internet), and went to the closest one that very night. It turned out to be a gay-lesbian alanon meeting. I was welcomed and they were friendly, but it wasn't quite the meeting I was looking for.
My only real problem, looking back, was not keeping up with the meetings that I did enjoy. Now THAT was a mistake.