Boyfriend's money?

Is it okay for my boyfriend to give his kids mom money when she needs to...?
I will give some background, I meet my bf at work we been dating for 2 years n living together for 1 year and 7 months. I became pregnant on November. My dad got him a job with him where he's his supervisor n he makes way more money than he use to, bc of the baby. He has two kids with his previous relationship, n he use to watch them evey week from 7 am to 6 pm n then he only worked weekends n 2 days a week. I was the stronger income in our house hold bc I didn't had kids n I was working more n made more money. After my dad got him that new job, he need it someone to watch his kids bc their mom worked too n since I'm pregnant he asked me to stay home wt them, I thought it was for a couple of weeks which became 3 months n I had to leave work wich I been depressed about bc I feel I don't have my own indepemdence. This wasn't permanent tho just till we all got situated, I had to get up at 4 am to get his lunch n breakfast rdy, then kids mom will come at 7 am to drop the kids off, one is 9 so I had to bring him to school n stay home wt the 3 yr old. They recently left on vacation n when they come back the little one is going on daycare bc I'm dilated n my doc send me for bed rest. I notice my bf doing money transfers, they still have linked accounts, wich I'm not ok with but I don't like arguing but I've told him how I feel. He told me kids mom was paying half of day care bc he also pays her child support. They have their own agreements. He told me he paid half but I found out he had gave her twice as much of the money he gives her every month for child support. Last night she called him that her n the kids where coming from the trip the next day, all I could hear was him saying, "yea, that's ok" "yea"
I see he has another money transfer this from last night, is a leaser amount but I find it odd. 
Now I'm the kind who don't like taking money from him so it's been hard for me without my job bc I haven't been able to get my baby all the things she needs n I feel like I'm behind, I'm due in 9 more weeks n I got nothing. He said he wants to wait till a few weeks before to get the baby stuff, n he's always complaining he don't wanna spend money bc things are expensive. He just wanna be home all the time n he's not really interested in getting the baby things rdy. Ik is his money, but is it ok for him to just give her money n be so cheap when it comes to our unborn baby? He makes good money weekly, getting paid when they can't work. And the only reason he got it was bc my dad wanted to help bc of the baby that's coming n he wasn't making enough before not even for the kids he already had or for house hold.
Is it ok for him to give her money when it's out of the child support or day care agreement? 😕
Just before I say something to him I don't wanna be unfair, please help 😞