Is it not only wrong but also adultry if my husband and I separated not legally memorial weekend but went back and forth about it and continued to do married things until July 5. Within a week or so he is living with someone else. He's had or three year old daughter not only around her so soon but his girlfriend spent the night together with my daughter

Technically it is considered adultery.

I agree, you still share your last name. I think that if you guys are not living together and have no hopes of getting back together for whatever reason then you should just get a divorce. But if you are still playing husband and wife from time to time then you need to suck it up and let all of the extra lovers go.

Well you have legal adultry from the state ( not that any of them have, and those that have don't inforce) any laws. It may be used as a ground for divorce, but then most states do not even require a reason for divorce but a few do. It may help some in a child custody agreement, but even that may not help in some that merely look at the type of parent.

Now in the eyes of the church, it is, but at what point it stops being will vary by church teachings.