Just need to scream!

Hi all. 
          Just warning..This is a moany topic so I won't be offended if no one reads as really long sorry 
Ok so met my other half 6 years ago through a friend  we got talking about the zoo as id been there that day with children I nannied for and he was saying he has been with his kids. So from the start I knew about his boys who stayed with him at weekends when the ex let him see them. 
I always said never date a man that's older with kids again ( been their done that ) not for the 'baggage reason just maybe different stages of life etc. But due to friends cancelling on a group night out we ended up going out and from then starting seeing each other etc. 
( at this point I lived with parents he had just moved back with his) 
The weekend we decided to properly date exclusively his oldest son was down at his aged 15 at this point ( can't fault his son he is lovely) and cutting it short the son ended up being kicked out by his crazy mum ( she made him choose nastily between her and my other half a d when he refused stating he just wants to see his dad she picked his stuff x d three it out the window and kicked him out) and of course that ment his son then living with him. ( I completely understood and was fine with it ) 
We moved out togther and brought our first home a year later with of course the oldest son too we brought a three bed house so it could support us three and space Incase the youngest was ever allowed down by the crazy ex and my plan for a child of our own. Unfortunately the master is a silly shape meaning our wardrobes at this point were in the third bedroom. 
First night we moved in the oldest got scared there was a ghost in his room ( aged 16) so came and slept on the floor in our room for a week! 
( suddenly lost was the new house 'sex'  which I'm gutted about but obviously over it ) 
Things then were fine and the youngest was allowed to visit every other weekend when his mum saw her new partner. (  son aged 9 at this point) and the oldest would visit his mum like every month so we had like a free house which was nice. 
One year after that the youngest stated he wants to live with us ( aged 10) so of course we welcomed him had to go to court and set up our third room for him ( the one I had planned to have for a child of my own) 
One year after that he wanted to move back with mum ( she was blackmailing  him as we have since found out in a bad way such as suicide threats if he didn't come back etc) so we respected his wishes and he moved back to his mum and we didnt see him then as she refused to let him have contact with us and his brother unless his brother went there. ( different towns) 
A year after that me and the other half decided to have shot at our own child but I lost my job so we put it on hold. 
The oldest then lost his job and was promised by his mum that her partner would give him a job but he had to move back to London with them so he could be taken to work each day etc so he did and soon found out there was no job so moved back with us and found a job here. 
I got a new job luckily easily and a year after that decided that we should try again after 2 months of not preventing being pregnsnt the oldest son comes back from holiday engaged to his 8month relationship with girlfriend. I was gutted as me and  other half aren't engaged and made me wonder about my life and caused a bit of arguements between me and my other half plus that fact the sons fiancé was like staying over all the time and I just felt like my home was being taken over and no privacy. 
3 months after that they annocced they were pregnsnt ( aged 18 and 20) I was gutted not that they were pregnant as such more like I would then be dating a grandad aged 28 other half is 38 without a child if my own. My head was then totally messed up. I just felt where the oldest wasn't at this point talkin to his mum I couldn't provide any support to the couple as I had never been through it to give advise. It was heart breaking and wondering if I'd ever have that feeling if being a mum myself now my other half was going into another phase of his life grand parenting. 
I straight away didn't want to be pregnsnt at the same time as them it would be strange to think father and a son comparing baby scans etc so I stop trying instantly. 
8 months later - 4 months ago they moved into there own old place ( mother and baby unit) had their baby who is gorgeous!!! Once I mentally accepted it and that any child I had would have a nephew younger than it I was excited to think about having the house to ourselves again like every couple wants especially after never having that chsnce so far. 
We both decided that it was again time to try for a baby of our own now we had the space and were able to have the fun of freedom in our own home and my head had taken in that life doesn't go to plan. 
We sat togther looking at nursery stuff etc and how and where we could home the baby eg in which room still allowing us to keep the storage in the the is room plus laundry stuff that don't fit in kitchen etc. 
Sadly my grandad passed away this month but shockingly I was left with a huge inheritance  when his land and properties sell which in his will words must be spent wisely lol. 
So we thought a loft conversion would be the best option as we love our home and have put so much time and money Into it already to make it how we love it could be slightly bigger that's all. So we could have a room for a child of our own a laundry room for setting clothing ironing etc a master room with wardrobes :) :) and of course a space for the boys should they need or want to stay or just general spare for guests or baby sitting the grandchild. 
So I'm so excited and straight away came off the pill to try 
2 days after being on cloud nine knowing that even if the money took a year we could have a child in our newly spare room after oldest has just left :)
The youngest turns up after 3 years of no contact expect through ps4  conversations in secret from the mum. Staying he is old enough to see past her lies and wants to live here as she is again making him chose between his brother , baby nephew and his dad ( we live close ) and the youngest said you can't do this anymore I'm seeing dad u can't stop me 
So my spare/ baby room is now his room. 
Both boys are lovely and no problem is never turn them away ever but soooo pissed off As I feel each time I get to have a bit of me and other half time and our child chsnce it's taken away. 
It's ok him living here if we get the conversion eg planning permission / ability to convert it. But if not then I have no where to place my own baby as Third room would only fit in a travel for nothing else as wardrobes have to be in there. 
I feel funny about trying for a child and the excitement about trying has gone as I feel restricted to the bedroom and trying to be quiet as he is just moved in so won't be settled yet. 
Feel so upset :( has anyone ever been in situations similar? 
I always have been so welcoming to the boys and took them on as other half isn't really a responsible dad in the sense of lacks the ability to think about food meals times washing clothing routine clear boundaries etc that children / young people need but come on why can't I have a chsnce to do all that but know what being a real mum feels like!!