Husband has breached separation agreement by allowing the kids to sleep overnight at his girlfriends. Do this constitute emergency custody?
Or should we ride it out since we have already filed for full custody.
No, that does not count as an emergency custody (or ex parte custody) situation. As long as it is clear in the separation agreement that that was not allowed to happen, then you may be able to file for breach of contract.
You are still eligible to file a breach of contract lawsuit, even with a custody action pending. Without knowing your exact circumstances, it may be more advantageous to proceed with the custody action that you’ve already filed.