Idk what to do

So, I posted earlier this morning about my SO not coming home or answering his phone after a night out for drinks with his friends.

My SO likes to go out and he has a shit ton of friends from work . I moved to Miami later on in life and I don't have very many friends nor am I the going out to party type of person. Having said that, I do not expect my SO to stay in the house because I'm not a social butterfly like him. So he goes out with his friends on the weekends but we agreed 3 was the latest he should be out. So he gets off of work Friday ,comes home to chill with me for a bit, then he gets dressed and is off to have drinks with his friends. I'm 35 weeks pregnant and I wake up multiple times throughout the night just to pee. I'm also used to him being next to me so sleeping in a big ass bed with so much space also makes me wake up multiple times. Anyways... I get up at 3:30 and I think oh hes probably on his way, I'm not going to call him now *falls back asleep. Wakes up at 4 still not home so I call like 500 times and he doesnt answer. He's always on Facebook so I check to see when the last time he was on facebook and his page says 2 hrs ago.

So at this point I'm thinking, he is sleeping most likely with another woman. My heart drops as i start thinking of all the things he could be doing. My poor son can sense it he starts moving and kicking, so I try to calm down and I go back to sleep.

I wake up again at 5am to pee. STILL NOT HOME, still not answering the phone.

then he calls at 5:15 sounding like he had just woken up and i can hear the engine of his car, the guy had to be speeding.

He says he was too drunk and pulled over on the side of the road and fell asleep. As much as I want to believe him I dont. Any who I screamed at him a bit and hung up thinking he'd be home in a few. 30 min go by and hes still not home. I call back and ask where he was and he said he was on the turnpike, I'm like , so you were all the way in the city? ( we live in a town right outside of Miami) He didnt get home till about 6. With traffic it takes you about 30 min to get from the city to our town. At 5am the turnpike is crystal clear PLUS I heard him speeding so he must've been further out than the city.

Not to mention his coworker had just recovered from surgery and he said he was out having drinks with him then on the phone he says "baby remember I told you it was Will's birthday" I'm like wtf are you talking about? you said nothing about a birthday you said you were out with Officer Cadent for drinks after his surgery.

He came home and just kept saying hes sorry. I honestly am so angry I just dont even know what to do or say to him. Hes still asleep while I'm in the nursery trying to get some school work done to distract me. What do you guys think and would you believe your partner?