"Ages is just the amount of years you’ve been on the earth it doesn’t equate to maturity." Some older people lack maturity but it's rare. Life experience is what leads to maturity, and that is only gained by living and that takes time.
While teen parenthood isn't the end of the world, I have friends who were teen parents, but it really isn't ideal either, it makes life much harder generally for parent and children. Maybe not a popular view but it's true. One of my friends that was a teen mum recently qualified as a barrister but we're now in our late 40's and it's been a hard slog for her, she herself would tell you that's not how she would have done things if she'd really understood how hard it would be.
"I'm sorry but you sound very immature. Some of your responses are like a child stamping their foot because they can't get what they want!" Totally agree
'I want a baby and I want one NOW!'
"He decided that he likes the idea of him being responsible for contraception" AWFUL idea! Rhythm method is basically useless. Condoms are not great for reliability in real use stats, hormonal contraception for the woman is far more reliable, but I suspect you know this and are hoping it works in your favour and an "accidental" pregnancy will occur and you're hoping he'll feel so guilty because "he was in charge of contraception" that he'll "let" you keep the baby - disaster written all over it!! He may well push you into another abortion and as a result you will very likely resent him and that will destroy your relationship. Or you have the baby and he resents you and THAT destroys your relationship.
"he’s said if it happens without us trying it happens." Such a ridiculous, immature, irresponsible attitude to something so important!
"Everyone keeps mentioning marriage. I personal do not believe in the constitution of marriage"
Why?!
Your childhood sounds very chaotic too which may be another reason you're so desperate to create a family of your own that you think won't be as chaotic - yet you're actually MORE likely to create a similarly chaotic life for YOUR kids by rushing into having kids when neither you nor your partner are really ready or mature enough to handle the responsibility.
"he says he doesn’t regret the choice he made because he wouldn’t be happy in Japan" he can't possibly know that if he hasn't experienced it. I would thoroughly recommend revisiting this idea.
"I never wanted to go to uni, not everyone needs to" again - that feeling may well change. Your partner in his chosen field of work would DEFINITELY benefit from doing so, non graduate employees in his field are ten a penny, frankly it's getting to the point that to have a decent career in that field, really you need a post graduate level of education!
I've been to uni twice - both times as a mature student, I wasn't in the right frame of mind for it at 18 as I was dealing with the aftermath of my own chaotic childhood. I wasn't ready or interested in going to uni when I was younger but as I gained more life experience and learned the realities of the job market it became clear that to have even a chance of a decent income meant having a higher education. I would say that's even more true now.
To be dismissive of that is ignorant and ill informed to be honest.
"My mum managed perfectly fine being a single mum" 'managing' and 'thriving' are very different things. Did you have and get to do everything your friends did? Have you talked to your mum about the realities of 'managing' like this, have you even discussed the negatives? You seem overly focused on the positives of parenthood and are very deliberately avoiding thinking about the negatives.
"We wanted to experience a little bit of adult hood without each other, to “find ourselves” as people say." But you didn't do that! 2 months is nothing! It's barely longer than a school summer holiday! "Finding yourself" takes years not a few weeks!
"He’s dreams changed because of me" wow! Peoples dreams do NOT change because of other people preventing them from pursuing them.
"I am a full blown atheist." Ffs marriage has NOTHING to do with religion! It's a LEGAL contract that ensures protections for the more financially and legally vulnerable partner AND indirectly any children of the relationship.
You don't even need a fancy wedding, you can book your local registry office, turn up in jeans and have 2 strangers as witnesses if you wish.
"We agreed to split everything evenly when moving in"
Meaningless in the event of a split. Hugely difficult to deal with if your partner becomes incapacitated or dies.
You are completely vulnerable without marriage exactly!
"I was waiting on the flounce to happen" fairly predictable really