Not exactly what you asked for, but ... My second marriage made me incredibly insecure! I do/did have some attachment issues resulting from a weird childhood, poor self-worth, etc, but had reached a point where I was confident, successful, and happily single.
Cue the bloke who would perceive all this in me (much of which I didn't even see myself) and systematically work to undermine my new-found security. Or "keep me on my toes" as certain types might put it. He changed his mind inexplicably, disappeared without explanation, and gave me increasing cause to fear he was cheating.
There's more. In short order, I became an anxious, clinging, suspicious wreck. I didn't even understand what he'd done until later, in therapy that I'd undertaken because I believed there was "something wrong with me".
That New Year's desertion was a cruel, vicious thing to do. Coming back but letting you know he wasn't sure: also cruel. It's very demeaning to you - if he couldn't show & tell you he wanted to be with you, what the hell was he doing there?! Only an insecure person would put up with that, and it's guaranteed to make her even more anxious.
What we need - you & I, and everyone really - is to know our partner values us, takes pleasure in our company, respects us, is there for us. I give this to my partners, and I bet you do, too. We deserve the same in return. Our relationships should improve our lives, not destabilise them.
If you're hoping to change him, don't bother. It's irrelevant whether he does this to you on purpose or is playing out some deep-rooted pattern of his own (probably a bit of both). Start reducing your investment in this marriage, start detaching. Start honouring the woman you were before this. Start therapy.
And good luck 💪