BS here,
I think you're making a decent effort. Others have pointed out some areas you may want to focus on like proactively getting the lie detector test, etc.
As a BS I can tell you that the hardest thing for many of us to overcome is not the length of the affair, who it was with or even the affair itsself. Yes, those elements are painful, but for many of us it's the effort that was put into the affair. WS often go to great lengths for their APs. The planning, logistics, 'plate-spinning', juggling and energy expended is what gets to a lot of us. Energy and effort, given freely to the AP and with reckless abandon, we've rarely if ever seen in our relationships with our WS.
Also, there are the risks, professional and personal, they take in order to carry on that gnaws at many of us as well. You stated you had sex with your AP 4-5 times but only met once outside of work. I take it that you were having sex at the work place? Consider the risks you were taking. Doing things at the work place is, sorry to say, nuts. Hindsight being 20/20 I think it's safe enough to assume you'd agree with that assessment. If you'd been discovered the results would have been catastrophic, but you did it repeatedly, like many other WSs. Also, you stated that the affair ended 16 years ago, but later said you left the job 5 years ago? So, you were there with AP, and anyone else who may have known/enabled for 10 years after? How do you think that made your BH feel? He probably felt as I and many others have felt, like the second fiddle. The consolation prize that gets settled for.
I want to suggest that being a good wife and mom, being present and involved is a good start, but it may not be enough. It shouldn't present too much of a challenge to be involved in your family's lives at this stage and it's what should have been happening from the start. You may want to find ways to really put forth energy and effort, comparable to what you gave AP, to your family.
For your husband, most men respond well to acts of service as long as they're consistant and genuine. You may want to introduce some new things into the bedroom, slowly, being mindful of him getting triggered. Plain vanilla sex in a plain brown wrapper probably may not really do it for him. He may enjoy it, but in the back of his mind he may be thinking you put more enthusiasm into your time with AP, whether true or not. But not just the bedroom. Does your BH get to come home to a clean and orderly house? Yes, I know you probably work a full time gig too, but if the house is straight, despite you having a full day already, I think it will show that you're putting extra effort into your relationship. Does he get to come home to a good, stick to the ribs meal, at least occasionally? I know it can be difficult, but again it show effort as long as it's consistant. In all ways for your BS and kids, if they're still home, try to dig deep and CONSISTANTLY go that extra mile. Show him with your actions that you WANT to be there. It may not be easy, but I think it will be worth it in the end. Good luck!