I didn't see your thread when you first started it, I agree with everyone that if you have lived with someone long enough, you know when something's out of alignment. Interesting to see your update.
The most devastating remark was that if we were starting over again he wouldn't have had three children, but would have stopped at one.
His reasons were time constraints and financial stress.
I'd be lying if I said there hasn't been the occasional moment when my partner and I have thought about the contrast between life before and life after DCs but to hear your DH phrase it so plainly must have been startling.
Yes perhaps you aren't always attentive to him because you've been preoccupied with the DCs, and he might somehow have taken that as a sign of rejection. Equally you want him to be your partner, not another person to take care of. It wou;d be nice if he didn't wait for you to ask, just picked up the slack.
I expect you've tried explaining, it's not that you don’t care about him, but is very difficult to stop thinking about the DCs and their needs, even during after they've gone to bed. It's challenging to refocus energy on him.
If it's not about cherchez la femme, I would say this hinges on money and financial stress. But if he is normally open with family finances and you have access to statements and everything and haven't noticed any severe dips and outgoings, that seems unlikely.
Just a long shot, has he harboured any secret health fears. Some sort of leaning towards hyphochondria as he gets further into middle age?
Are you still going away with MIL this summer? It's crucial to have alone time with your DH, but the next best thing is a change of scene for all of you.