Cheated on while pregnant, advice needed

I don’t really have anyone to talk to besides my husbands family and I know they more than likely want the best for him. I know I can’t talk to my family because I can always decide to forgive him but they won’t be as forgiving. I have come here as a way to get my emotions out and seeking advice. Prior to this, husband and I spent every day together and there was no situation that was even similar to this. He was super careful in every situation so I don’t know where this came from. I don’t recognize this behavior and neither does he. To the story: Husband and I just celebrated our 1st relationship anniversary on the 4th of July, and it will be our 2nd month married on the 8th of this month. I am currently 27 weeks pregnant and have been generally pretty happy throughout my pregnancy. My husband and I decided to drive down to the place where we first became a couple, Los Angeles and celebrate our anniversary here. Yesterday, one of his friends calls him knowing he is in the area and wants to hang out so hubby invites him to the hotel pool, and his friend brings his sister with him. Everything was cool, husband, friend and friends sister were all having drinks which were pretty heavy on the alcohol seeing and they were mixing their own drinks with a bottle my husband had bought. Some girls who were staying at the hotel were being came up to our group because of the music we were listening to and we ended up joining groups because my husbands friend is single and was into some of them. Now, his sister was getting pretty out of hand quickly, talking about her guy problems and was going around asking these girls if they would be interested in a foursome with her and her guy. She was telling me she was super horny and mad this guy wasn’t giving her the attention she wanted. At some point I caught my husband taking his prescribed adderall while drinking and got pretty upset at him because he had lied to me when I asked him if he was taking one. One of my cousins came to the pool, he brought his girlfriend and one of his cousins. When they got there, husbands friends sister was passed out on a pool bed because she had gotten so drunk. She slept for 3 hours and then woke up and was talking to me and the group I had brought. She then decided to get in the pool, up to This point my husband was not acting disrespectfully and it’s out of his character to do anything like he did. But he jumped in the pool after a while of her being in there. Out of pure curiosity I turn around after he had been there for a bit and see his hand up her vagina. When he locked eyes with me (because I can imagine he had been looking at me the whole time) he still took his time (so I think, it was only around 3-4 seconds but Everything was slow motion for me) pulling his hand out and I couldn’t believe what I had seen so I turned around to my cousins gf and the other girl to ask if what I had seen was real. They confirmed it and told me they didn’t want to tell me because of everyone around and I jumped up and pretty much told him to get the f out of the pool and said some choice words to her. I tried staying as calm as I possibly could because of the baby and not wanting her to feel what I was feeling. Husband is regretful, says he’s going to change. But he questioned me and asked me if I was sure that I had seen what I saw correctly which made me so angry. No more alcohol or any substances of any kind. He has agreed to go to therapy both individually and in couple and he’s willing to go to AA and NA. He is also going to look into his friends as this is a big factor for our problems. Most of his friends are partiers who like to drink and so drugs and that is not the lifestyle he is in anymore as he’s going to be a father. He has said himself he needs to reevaluate all his friends and get himself out of that lifestyle because being in those situations is how we ended up here in the first place. This is obviously not what I hoped for my first child and I don’t want her to grow up in a broken household but I just don’t know what to do. I just don’t know what to do anymore, I feel like I’m depressed emotionless and numb at this point. There is nothing in our relationship which leads me to think he would be seeking comfort or attention from someone else seeing as I give him everything he needs. We had sex regularly and I always paid attention to him. I thought we were so in love but I don’t know.