This is almost exactly the experience my wife and I have had. Only recently have we begun to address it; so far so good, but way too early to declare victory.

Communication is key; including (or maybe especially) the uncomfortable topics. A few things that have helped us:

1) Told my wife to tell me when she is in the mood, even if we can't do anything about it at the time. Reminding her of a sexy text message, comment over the phone, or even whisper in my ear is sometimes enough to bring her back to the way she was feeling at the time. (She says this is the most important change because her libido isn't gone, it's just lessened, and it helps her prolong or "reschedule" what might otherwise be a momentary urge.)

2) We found/created a "sex game" that we play when she's in the mood and we have the time. It simultaneously gets us talking about sex in a way we hadn't before and gives us an "above average" sexual encounter to remember and provide some consolation if the rest of the week is a bit slow.

3) Immediate communication. If I'm not sure why we haven't had sex, I have to ask. My wife made this rule, because she hated the idea that I might start resenting her without her knowledge. Of course, it's on me to not abuse this by being unrealistic and it's on her not to give in just to appease me. That was a dual promise we made to each other and have thus far been able to keep.

4) Extra dates, especially overnights or a joint day of "playing hooky". We've always been pretty good about getting a babysitter or one of our parents, but this becomes extra important as you work through this.

5) A little more alcohol. Nothing excessive, but take the cab/Uber so you and your wife can both have a little more. The least important of my list, but does lighten things up a bit.

The change is slow and steady, with peaks and valleys, but her libido and my contentment have both improved greatly. I wish you the best of luck and don't want you to get down on yourself. I think everyone has dealt with regret for not properly appreciating something until it was gone.