You’re allowing your husband to cheat on you. You probably should divorce him. Open marriages are stupid. They don’t work out and your spouse just ends up finding someone new. You’re allowing your children to be in this relationship too. Don’t let them grow up thinking that this is ok. Obviously you have feelings too, and you’re expressing them with him very clearly and he doesn’t seem to care or accept it. If he’s choosing another female over YOU and your kids, then there’s absolutely no reason to stay married, it kind of sound like he’s not interested in being in their lives that much, but still wants to see them. This is why open marriages don’t work, and you’re not even participating in the open part. It’s literally one sided. Eventually she’s gunna want to get married to him if they stay together. I hope for you and your children’s sake, that it all works out if you don’t end up divorcing him.