Why does he have PR?
Why are you having a second child and he is planning on moving away, and yet you anticipate having both babies with you?
You sound absolutely bonkers tbh. Dropping dd off at his work because you need to do uni stuff? Taking his car keys and disappearing so he can't drive to work? Then calling him because you left the back door unlocked?
In all honesty, he might be stressed and a pita, and he might be utterly BU to have started the whole 'I fancy another woman at work' thing, but the pair of you sound like absolute disasters as a parental unit. And in his shoes, I may well have decided to make my own childcare arrangements, as the alternative is you turning up at his work, dumping a kid, and going off for the next important thing (hospital appt/ uni work/ whatever it might be).
How does dd react when you lob stuff, screech, stuff her in the car in the middle of the night, or drag her to her father's work and dump her there? To say you don't expose to this is utterly incorrect, I'm afraid, and as she gets older she will be more aware. And you are willingly adding another child into this farce? Because you want a bigger family?
You claim that for less than a year everything was perfect. The disaster has been rolling on for longer. And now you will be more stressed, more freaked out, have less time, less sleep, and will need him to bail you out even more for real or unnecessary reasons (back to the uni work)
You are also utterly kidding yourself. You claim never to have any problems raising dd, coping, you have always managed etc etc.
Like fuck. You were so stressed you dumped her on him AT WORK because you needed to do uni coursework. That isn't coping, my lovely, and in no way is it the reaction of a sensible and sane mother. And now you will have two, that for various life reasons, you will want to offload at various points when it all gets too much.
I'm all for studying and improving life chances. But it is fecking hard with little kids. And you don't get the opportunity to just dump them when it all gets a bit much. Especially to a partner AT WORK. No wonder his employer is not a huge fan, really. Having an employee whose partner has MH issues (as well as various diagnosed and investigative health issues) can be hard work.