Childish Partner Raising Children?

Hello everyone,

I'm new to this forum and have spent the last week reading posts that have been an eye opener for me - Thank you to everyone that has posted, I have leant a lot from you.

My partner has non medicated ADHD and I am struggling with two things in particular. Childish behavior and blurting things out without thinking.

My partner has had ADHD for his whole life and has all the classic "traits" of the condition. I feel I deal with most "traits" well. After a LOT of research on how his brain works, I understand that he cannot control most of these and I have adjusted myself appropriately to keep things running smoothly. 

We are at the point in out relationships where marriage and children are something to seriously think about but in all honesty, I really have no idea how that will go - especially the children part!

He is immature and extremely childish 90% of the time - which is fine, that's part of who he is and I understand that completely. It does at times wear me out though. He also says ANYTHING that pops into his head and sometimes the things he says are not the nicest and can offend me. This blurting out then leads to a whole other problem that I absolutely CANNOT deal with... He will then twist what he has said, tell me he didn't mean it how I took it, downplay what was said, or if he thinks I didn't hear him properly and ask him to repeat himself he will say something completely different that kind of sounds similar to the original statement. I think he does this because he has seen how what he has said affected me and has now had a brief moment to think about it??? I don't bloody know. During the beginning of our relationship this blurting out stuff was really making me question my sanity, I genuinely felt I was losing my mind - how on earth can I misinterpret, not recall properly and take these comments the wrong way so frequently?? He would say things like "you need to get a cat scan" or "the antidepressants are really affecting your memory" (I was on antidepressants for anxiety). I really feel he is so very good at being a gas-lighter he doesn't notice he is doing it. It makes me want to record everything we say to each other.

Anyway, I digress, sorry for the mid post rant. 

The reason I am posting today is to gain some insight about ADHD partners becoming parents and raising children. There are so many things I worry about. What is the chance of my child having ADHD also? How will my childish partner cope with a baby/child, will he step up and act hes age? If not, how would I cope with being the only adult in the family? Will our child learn and take on the traits of my partner even if it didn't have the condition? Will we be able to come together and be great parents together or will the issues we face now become worse? Will the gas-lighting make me doubt myself about parenting? The questions I have about this are endless. 

I would greatly appreciate any input with this. Can anyone share their own experience with an ADHD partner becoming a parent and raising children?