Some clues - your own deadbeat dad and previous toxic RS tell me that your self worth has been set v low due to your childhood.
Therefor you tolerate v low standards because you were not cherished and valued by the most important man in your life. This neglect has set your pattern in the same way that his overbearing mother has set his.
Start looking at your own emotional growth - to fill that void that the deadbeat dad left - because that wound will trip you up and lead you into more unequal, unsatisfying, and dysfunctional RS even if you finish with this guy.
Anyone deserves more than this. This is not kind and respectful. Don’t waste a minute more of your precious finite years on this one. He is not your happy ever after - he will not fix your early childhood wound and provide the dream of home, marriage, baby, happy family.
But if you take some time out to fix yourself you will attract and only accept a genuinely emotionally healthy, positive, motivated and equal partner who will be a wonderful father.
This guy will be a deadbeat dad to your DC, just like he is a deadbeat BF.
Well done to you for being independent with your own home in your 20s - meet someone of equal worth, racing to build a life with you - not some loser in his 40s with nothing dragging his heels.
And his creepy Mum pushing him to TTC and buy a house with you YUCK.
You are a star who has been let down early in life. Fix that bit through therapy, emotional self development and all will be good.
Leave now and in a few years time when you are in your bigger house you will look over to see a great guy pegging out the washing / changing a nappy / bringing you cup of tea etc and know that it Sept 2020 you chose a path that made this happy family happen.