You said
It's cuz of his upbringing, his mum did everything, he didn't lift a finger.
and
I have to stop it all now, my mum has had a lifetime of picking up after men and I can't do the same.
and
^He's also un tidy and in his room ( I sleep in with ds) his clothes are everywhere. Even the ones I've washed and put on his bed.
I do all this for my teen ds but my dp is a man yet acts like a kid.^
Read it again. Yup. You're doing exactly what both your own DM and DMil have done. Now its easy for an outsider reading what you said to point that out to you, and maybe much tougher to notice in day to day life but once you realise it, you can do something about it.
Children aren't necessarily good at noticing what needs doing, remembering weekly chores, initiating them and staying focused enough to finish them. I reckon the same is true of adults who never learnt as children.
I find this 'keeping house' thing hard myself, so I'm not coming at this from a judgey point of view. I'm kind of self-parenting myself to learn the executive skills I didn't learn as a child/teen. So that's the approach I'm going to suggest you take with your DP because you say that other aspects of your relationship are good and that you just want this fixed. I do appreciate other (fantastic) mnetters will say its not your job to teach him this stuff that he should just figure it out on his own and they may well be right, particuarly if he is a man-child in other respects. I'm only suggesting this because its something I'm learning at the moment and I realise its hard to change habits and since you've said that he is willing to do stuff when asked directly it might work.
For starters do what was suggested above about working out how many hours you both spend on work/household chores/childcare/lesuire etc. Sit down with him and point out that it is unfair as you are a family and should all be involved in the running of the home and child care. You particuarly expect to have similar amounts of lesuire time to him, you have been at 'work' all day too but don't get to clock off, never mind your night shift. Obviously the nature of your bf might mean that you take your lesuire time in smaller chunks for the moment rather than whole nights out.
The solution is to work out a more equitable share of household chores. Your teenager should also be involved in doing his fair share and include your younger child as soon as he's able to 'help' you with any basic tasks even if its just putting his own toys in the toybox, because doing 'chores' with mummy should be part of his daily routine rather than him playing whilst mummy runs around after him.
So draw up a list of everything that needs doing on a daily/weekly/monthly basis to keep the home functioning smoothly, perhaps with a rough time estimate of each task. Negotiate with your DP and Teenager which jobs you each don't mind taking responsibility for and split the rest between you (perhaps rotating them so that noone gets saddled with the least popular jobs). You can decide whether to put in a family reward at the end of the month if everything is done, or not. I'm not big on reward/sanction systems, but some folk like them. I'd just expect a reasonable number to be done before lesuire time.
Pin up the lists for them to be ticked off as completed.
At first, because this is new to them, you will need to direct their attention to the lists on a regular basis. But at least you're not having to micromanage individual chores (though if they are taking on something they haven't done before, supervision may be necessary). If they can get into the habit of checking them at a certain time/s of the day, it should eventually become something that you have less and less input into. And you can adjust the lists if you find that something isn't getting done repeatedly but you are all responsible for 'policing' the lists.
I've suggested lists. You don't need to do lists. But they might be useful for your teen/DP who don't find it easy to keep this stuff in their minds at the moment.
I do realise that this practically parenting your DP. I understand that it isn't appealling and he ought not to need it. But I'd frame it more around getting the whole family to run the household, with the lists being particuarly for the benefit of the teenager.
I need lists to help me keep track of what I need to do, sorry if it seems like it's for little kids. [shrug emoticon] But you can do it as formally or informally as you like.
I don't think you are being unreasonable about the tobacco, it really is a danger to a baby at the age of putting things in his mouth. But knowing you have OCD you probably need to make sure you are being reasonable about your general expectations of cleanliness.
I know I'm rambling, I think its because I suspect with the childcare and lesuire issues that this isn't just a household management problem, but if its that you want to improve then delegating chores and carving out some lesuire time (even if its just short bursts while you go out for a walk/have a bath/read in your room/go out for some non-grocery shopping/a friend's home for a coffee/etc) is probably how to start.
Your DP looking after the baby is not babysitting, its part of his job as a dad.