A possible middle ground could be to stay in a relationship with him, but make it a "dating" relationship rather than one where you live with him or see him every evening and all weekend. This would make him less of a feature in your children's lives, and keep them from growing more attached to him. It would give you regular time without him, and thus reduce the chance that you'll go into "boiled frog" mode where his controlling behavior ramps up slowly until, before you know it, you've lost all self esteem and all ability to stand up for what you want or even to know what you want."
You know it is funny, but now that I know about OCPD I almost think that this is not the approach for me. I asked him at one point after we started counseling if he could have a perfect world, what would our relationship look like. His answer was that I would have my own place and that I could come and go freely. (which was how it was during our blissful time) Moving out is exactly what would ease his OCPD because he wouldn't have to accommodate me living in "his" space.
Re: "I told him before that I understand that he is anal about the house, and asked him to simply let me know if there is something causing him anxiety so I can take care of it."
This concerns me. It suggests that all he has to do is tell you what to do, and you'll do it. The problem is that if you do manage to persuade him to tell you what to do, he will likely exercise that privilege more and more. That isn't good for you, and it really isn't good for him either - it's not healthy for someone with OCPD to have all of their control issues complied with, any more than it's healthy for an alcoholic to be handed a drink every time they have a craving. It would be better, IMO, to set boundaries, refuse to be told what to do, and put the responsibility for their anxieties on them
I agree with you. This was part of what I thought at the time was a normal part of adjusting to living with someone. I have my own anal things that I prefer, like I will separate knives, forks, spoons into separate areas in the dishwasher - he doesn't. I have asked him to accommodate me in this area. Now I realize that on his part I can never meet his expectations and so I need to determine what I am comfortable with and set my own limits. (also difference is I wouldn't be upset at him when he doesn't do it - I just correct it to make myself happy if I feel the need to.)
That doesn't mean that you never cooperate with him, but it's important to understand that it's probably not going to be possible to cooperate enough to make him happy, so you have to stand up for yourself and behave as if this is your home, too.
That is going to be the tricky part. More reading and learning is needed on my part and it will be good to get our counselor on board with this.
Thank you to all who have replied. This is going to be quite a learning process for me. I can say that he is not an angry person at all and is quite personable. He has been my mother's next door neighbor since I was 19 years old. He is 59 years old, and just retired after 33 years as a firefighter. I tease him all the time that he is George Bailey from It's a Wonderful Life because he is so nice and friendly that he knows all his neighbors and just anybody that over the years has traveled past his house more than once. He is very outgoing, friendly, and helpful to anyone in need. His big thing is his home and he did admit to me once that he is married to his house.
I write all that because I read so much on here about OCPD people being angry and hard to live with. He really is not like that at all. We don't "fight." If we have a disagreement, like when he finally will break down and tell me that I don't keep the house up and it is a disaster, it is a discussion between us.
I already am being more assertive about getting my needs met with him. Saturday night after dinner he went up to work on research on the computer and I went up and asked him to delay his computer work and come have a family night with me and kids. I could tell that it created a little angst for him to not dig right into finding a new pool pump, but he left that behind and we had a great night with the kids. Before I would have just left him to do his research and spent time with the kids by myself.
Looking forward to reading the links given to me and learning more.