Well, by reading the posts it appears this thread didn’t get off to a very good start.
My response to the OP, is no, unless it is something such as a funeral, baptism or a wedding.
Otherwise it can very easily be a danger to your faith as you will be hearing two different messages. Some here have said that things have changed since Vatican II, yes they have, but we can also see there are more people losing their faith today, leaving the Church and leaving God altogether.
Also, not everything has changed since Vatican II. People just think things have changed. It is still wrong to participate in activities that are prohibited. Most people equate that with communion but it can mean a lot more, such as listening to messages that contradict Catholic teaching, singing songs that contradict Church teaching, re-baptisms, Catholics marrying in a protestant church without permission, etc. Such as those would also be participating in something prohibited.
I married that person, and entered into full communion with the Catholic Church.
I like that. It is very good to hear. Unfortunately, though, many times it doesn’t work out that way.