Hmm, jury's out on that one tbh, Your DP somehow IS telling you in no uncertain terms that he has a say on what you do, with and without him. That his life and view IS more important than yours.
You have gone out with an old friend, one that clearly he feels threatened by, because you knew her before him, because of the singles holiday, and because she is by far the closest friend you have.
You say all the children, he expects you not to have time with your DS only, does he not have time only with his DC? If not, that's something that needs addressing too, they need time with their Dad only too. Are you doing the bulk of the childcare too?
This guy IS controlling, but in a different way to the previous one. It is control nonetheless.
Your DP is already wanting to know where you are and when you will be back. How is that different?
This is not about you BTW, this is about him. HIS control issue. With reassurance from you, it may be that he can learn to relax his grip. Maybe, maybe not.
But you do have to stand up for yourself again, you do have to state that you have friends and will see them, that it doesn't mean he is thought any less of.
However, if he stands in your way, tries to tell you not to see your friends, that you WILL think less of him and it WILL seriously hamper your relationship. Tell him that any one that loves another person needs to want to see that person happy, fulfilled, free and with a full and meaningful life.