Unsure what to do advice please

Have you spoken to a GP/HV about your postnatal depression?

Completely understand that mental health can cause a change in personality/you to act in a way you never would before. Does your DP understand that?

He needs to be supporting you, especially while you have a young baby, reassuring you etc. He needs to step up in that respect but you cannot expect him to simply forgive and forget if you're not trying to get help for yourself.

Focus on your new baby, enjoy time with him. Relationships go through a tough stage after a baby, hopefully you can get through it and there is no cheating etc going on.

The fact you have been cheated on before combined with your mental health could mean you're overthinking things/pushing him away. Could you try have a sit down with him and discuss things in depth? Explain how you're feeling?

PND completely changes your personality and your perception of things, people and everything. It's very debilitating. Please see your GP or HV.

I started taking them again but my DP wasn’t happy as he doesn’t think I need them when I coped without them during the pregnancy

It's not up to him though, is it? He should want what's best for you. Please see your GP and have a conversation with them.

Well done for getting the help you need, I know it can be difficult especially if you are surrounded by people who are not supportive.

Being home alone all day looking after children is very hard. It must be frustrating that your DP doesn't understand this. Could you leave him alone with them for a few hours so he can appreciate how difficult it actually is?

During the day, are there any local mom and baby groups you could go to? Do you have any mom friends to go out with?

You don't have to be normal with him and he shouldn't expect it when he's not being very supportive or affectionate towards you. You don't want to give your time and energy to someone who you don't even know wants you back.

Have you told him that when he talks about these other women and their problems, it feels as though he cares more about them, than he does you?

Have you told him you can't continue not knowing where you stand? That you need stability not to be walking on eggshells wondering if he's going to leave you.

Please speak to your GP. I think that you might be overthinking things.
You say that when you try to talk, your partner brings up a female colleague who off loads onto him. Could it be his way of saying that he’s getting it in the neck at work and is now getting it in the neck at home?
Maybe he’s finding parenting a bit hard too? He’s missing out by being at work.
You really need to talk to your GP about your fears and insecurities.
I’m sending you 💐

If he is so uninformed (or just clueless) that he can't understand depression doesn't just get 'cured' & can resurface at times of stress, like a new baby & being a SAHM can be lonely, is he going to be a supportive partner going forward? Probably not. I'd get back on anti d's: your health issue, your choice, not his. Then when you're feeling better & can be more objective, seriously re evaluate whether he's the right choice for you.