Please help

Hello. I am the boyfriend of my girlfriend. We are nearly 19 weeks pregnant. We are looking forward to our 20 week scan to find out if we are having a boy or girl. I am 41 my girlfriend is 27. We have been together about 10 months. But we have known each other for about 8 years. Some people will and have said that we got pregnant quick. But anyway. Maybe we did. This is our first baby. I was over the moon wen we found out about having a baby. Iv evan thought i couldnt make babies. If you know what i mean. So we are both happy about the baby. Im here anonymously so il call her mo. Latelly we are having problems with our relationship. We are arguing and sort of not getting on. I love her with all my heart. I really do. And our baby. Now mo has been living at her mams instead of at home with me. Mo says we have to have a break. For how long i dont know. Mo will say shes going out for a day like on a bus somewhere. And wen she goes im not allowed to msg her or ring her cos mo says she needs her own space and time. That i understand needing own time to her self. But i worry about her when she goes out. So wen she was out the other day i text her. And she went mad at me for doing that. I miss her so much wen she isnt here. But i noticed shortly after getting pregnant mo started to get very short tempered with me and angry. I have been thinking could this be coused by mo getting pregnant. Like hormones and stuff. We talked yesturday and mo said wen the baby is born he or she will stay at her mams house. Now that broke my heart. Cos we have lots of things here for the baby. Cot, pushchaire and lots of other things. Evan started the room for our baby. Sorry if iv gone on a bit but iv tried to tell you everything. I came to here to ask for help and just to talk to someone about this cos i have told no one . Not evan my mam. But mo has told her mam. There is more i have to say but it will take ages to say it all. So my main question is. The way mo is acting could this be causee by the pregnancy. I googled somethings and i saw a girl was saying that she hated her husband while she was pregnant but wen she had the baby she loved hime again. Could this be the same as us im wondering. And mo wont see this cos this is differant to the one mo has. Please feel free to ask any questions if you like.

Thankyou 😃