Getting over someone by sleeping with someone else

Okay. So I NEED OPINIONS.

My now ex so left me over a week and half ago. We did fight a lot but I think my hormones just went nuts this pregnancy. ( that’s when it started ) anyway, on Thursday May 9th everything was perfect. Legit we spent the day together. We are talking baby shower/ our sons name ( I’m 29 weeks pregnant ) we went out to dinner and went shopping. Then the next day he leaves, he blames how “toxic” and how much we “fight”. I never hear from him again.... ever. Before he blocked me on social media I did see his Snapchat score was flying by hundreds. And he was always active. ( he never used Snapchat when we were together and that was for a couple of years ) so I kno he’s talking to other girls... my friend also messaged me saying he is on tinder and he put on his bio he’s “ looking for someone to match his weird personality and wants to have fun” also saying how “ he’s moving into his own place in 2 weeks and can’t wait to start making some big $$” ( he just graduated nursing school too )

I’m so lost... I have been put on antidepressant medications and have to see a therapist twice for the remaining of the pregnancy. He was SO over he moon to have his first son. He went to all my de appointments.. he took my two kids in as his own.. We were 2 weeks away from moving into our new house. I’m so confused how this is even happening or why....

So the point of this is, do you guys think he’s trying to fill a temporary void and sleep with other girls to not be with me? I know it sounds funny. But do you think he really wants to be with other people or he’s just forcing himself to stay away from me? I’m just very confused.

Please give me some advice and no negative comments.