Sorry @Waitykatey I have only read all of your posts, so I hope I am not repeating something someone else has already asked.
You said that you both have adult children, just not together? Did your boyfriend ever live with the mother of his children, and if so, for how long please? Also, if they did live together, where did they live? I am imaging that if his parents house is quite large, they might have all lived there. If not, how many years did he live away from home, and if, as you say, your boyfriend is lovely, laid back, and helps with, or actually does, more of the household chores, how, and/or why, did his previous relationship finish?
I can't see any reason why his children's mother would want to break up with him, as he sounds almost perfect? I also can't see why he would want to break up with her, his partner, if he is as laid back as you said - what did she do that was so bad that he couldn't be with her any longer, if it was that way around?
If he lived for say 12 to 15 years in a property he shared with his partner/wife, surely he should have got over the feeling by now that the place he feels most relaxed in, and at home in, is still his parents house?
Anyway, I have several other questions I would like to ask in order to get a clearer picture, but in essence, and imo, the easiest and best way for him to want to, and be able to, relax the most in his own home - the one he shares with you - is for him to discipline himself for 6 out of a week's 7 nights, to come straight home from work, or after using the gym, to your joint home. If you are always late home on a specific night of the week, and he likes having a couple of hours just relaxing watching the TV, or reading etc whilst being totally alone, possibly in order to have no interruptions at all, then you should agree together that you will usually not get home until say 8.30pm, or whatever time suits you both on that evening. Obviously, If you wanted the same consideration, then another evening should be stipulated for that to happen.
Ideally, I think that he should still go back to his parents house once a week, after work, when his parents, or at least his DM, is at home, and have dinner with her/them, and then come home to you by about 9.00pm. If you are wanting one - known - evening alone like he does, to relax in your favourite way, than that should be the ideal evening for him to have dinner at his parents house.
Please explain to him that if he really wants you both to share a relaxed and happy relationship, you will probably both need to make some compromises, and doing that will probably cause some - or maybe even a little more than some - discomfort to begin with. Again, imo, it is essential that he trains himself into relaxing, and feeling most at home, in your joint home. If it is warm enough, does he like being naked, because he can, and maybe should, at least at the beginning, lounge around naked in your lounge, and/or pleasure himself if he feels like it, as neither of those things are something he could do at his parents place - unless they are naturists of course 🙈 *
For this relationship to be happy and fair, you need to communicate with other both calmly and caringly, and then work at it! It isn't being 'unromantic' for you each to put effort into your shared relationship, in fact, that is what real romance should be, not just some fantasy fairytale that would probably never happen in real life. Please don't let this slide WaityKatey, it seems as if you could have an amazing relationship together, if you as a couple, are willing to start making very strong foundations straight away. Good Luck OP, and OP's boyfriend, and hopefully soon to be partner!