About the traveling: DH and I did that together, with the kids on tow.
You know, that is actually possible.
Marriage and a family isn't something that holds you back, it just means you are a bigger team. But as a family, ideally, you should be a team. And if you want adventures, plan for them together!
The fact that he sees his lovely wife and kids as milsstones is just so depressing.
He is NOT a good father and he is NOT a good husband. Stop saying to yourself he is.
Ironically, if you would remove the choice from him by asking him to leave and start divorce proceedings, he woudl eb more likely to choose you.
But either way, get serious about lawyers and money, don't trust him t be honorable. Once he has moved in with OW (and she gets pregnant) things will change.
Don't take his word for anything, many men lie and then suddenly sluice all funds to OW and new baby....