Current living situation and ex

My ex and I have a baby, and we decided to end things for sure. Well I’m making it for sure. He still try’s to text me stuff that would make me change my mind to get back with him, but the relationship never works. We’ve been on and off for 3 years. Its not healthy.

So I agreed I’d coparent. The baby stays 2 weeks with me and 2 weeks at his place. The only issue is that I stay at my grandparents house. They don’t like my ex what so ever because of how toxic our relationship was and how he had treated me in the past. It’s irritating since I’m living at my grandparents house it’s their house their rules. If I leave my baby at my ex’s house for even a day they threaten to kick me out and I end up homeless. I can’t have that for my baby. My ex still lives at his moms house so he has nothing to worry about because she will never kick him out.

And to be honest my grandparents are also toxic too. They are one of the most ignorant people there’s no explaining anything rational to them. So I tried going out of my way to find a place for my baby and I, but I don’t qualify anywhere because I don’t make enough money. Which sucks because I have enough money for rent. All the apartments based on low income are currently unavailable except for this one apartment. It’s a 1 bedroom for 400 something a month and I am responsible for the light bill added to the monthly payment. Do you think that would be the best decision to take? Or should I wait a little longer? If I do then my ex doesn’t get to see our baby for a while? We agreed no court just because we want to be mutual.