OP, LTB.
I don't say this lightly, but he's showing the kind of red flags my ex did, and my ex is an abusive wazzock.
I left my ex after 30 years, and was broken, my DC both needed help for MH issues. I doubt your DC actually love him. Children will say they love the adults in their lives, because they are dependent on them.
If you leave (or get him to leave depending on the housing situation) I bet you'll get your DDs saying a lot more about him and not necessarily in a good way.
My DC told me a lot about what went on when I wasn't there, and it wasn't good. In particular, my DD told me he'd just walk into her room, often when she was changing clothes, and it made her feel very uneasy. He wouldn't let us put locks on the doors and refused to fix the bathroom lock. Yet he would be the first to complain if we went into the bathroom when he was in there.
Since we left, I've had proper, open talks with my DC, and both have assured me he never sexually abused them but that his behaviour towards DD had worried them.
This behaviour of his began to escalate as she got closer in age to the age I was when I met him (I was young and naive). I will never know if my ex did have a sexual interest in our DD. But she resembles me at that age, and I will never be able to discount it.
Re, and re-read the posts by people like Graphista and PurpleSpottedPony. They know what they are talking about.
And don't fool yourself into thinking you'd be able to spot any abuse. I've seen so many heartbreaking threads from people who said their parents ignored signs.
You posted here because you are uneasy about him, but what you really wanted was to be told nothing was wrong. You are already burying your head in the sand.
And abusive people don't show their hands immediately. It's often said that it takes about 2 years of living with someone before their true colours begin to show.
And those colours are showing now. He is grooming you all, and your subsequent posts are minimising his behaviour. And as part of his grooming, he is driving a wedge between you and your DDs. So, you'll be less likely to believe them if they do say something to you.
Don't show him the thread. I can guarantee he'll twist everything to make out you are the unreasonable one, and that he had only the best interests of you all at heart.
OP, your DDs need your protection, you actually sound like a good mum, so don't fail them now.