Adultery makes no difference at all to residence decisions, or to anything else in divorce, to be honest.
It is hard to divorce on grounds of adultery unless you are sure the other person will admit to it. It is better to go for unreasonable behaviour - for example, insisting on an open marriage when you do not want one.
Residency disputes usually come down to who has been the main carer of the children. In many cases, though not all, this has been the woman, which is why women tend to end up being the parent with care. However, you might be able to negotiate with your wife about what happens with the children. At 11, your elder daughter will probably have a view about it too.
It''s better for the children if you don''t have a dispute about it at all, but instead come to an arrangement that is best for the children. This might be living most of the time with one of you and with the other alternate weekends or one or two nights in the week, or it might mean living alternative weeks with each of you. It depends partly on how much you can co-operate and what is best for your circumstances and the children.
Best wishes,
Sadie