Think He Cheated While I Was Pregnant

We had been together a year when I got pregnant. He was happy, going to parenting classes, etc... Around 4 or 5 months I started showing and he started acting strange. Wouldn't have sex ( he said I needed to spice things up ), started kissing me only on the forehead, eventually was sleeping in the other bed or going out after work because he "didn't want to wake me". He worked at a bar where the closing time varied but as I had worked there too prior to the pregnancy, I had a good idea of when he should be getting home. We shared a car and one day instead of him taking it to work as he usually did, I insisted that he let me drop him off. It was my car after all. He became enraged and said he hated me and I was ruining his life. He had never said anything like that to me. It was a totally disproportionate reaction. Other things, odd things... sometimes I just got the feeling that he was giving me too much info, like trying to account for his whereabouts when I hadn't even asked. When he was home he would only watch tv, play games, or sleep. He refused to go on dates because he was too tired. We didn't go out my entire pregnancy. He kept his phone even closer than usual and was deleting things. I'd never checked it before but started. He said he always had to delete stuff because it made his smartphone work better. He had always been a heavy drinker and I thought maybe he was trying to hide the extent of his alcohol use, which had increased even more, and maybe the alcohol accounted for the late nights and erratic behavior. After a couple months I pushed the sex issue and it ended with me crying and explaining how physical affection is necessary for humans, and telling him how hurt I was. He said he just needed me to stop stressing him and eventually his sex drive would come back. Then he went and slept on the couch. Again. So... one night I followed him. I went to the bar where he worked and they were closed. I called him and what did he say? Why, he was still at work, trying to wrap things up. He was going to his mom's and the store after work and then would be home.  Strike one- saying you are working late when I know you are not. I went to the after hours bar where most of the guys would hang out and my car, which he was driving, was not there. Then I went to his mother's house and did catch him pulling into the driveway there. Maybe I had missed him in transit. I just sat on my information. Another night saw him out after work drinking with other guys, no girls. Left the bar with his buddies and went straight home. Then I got a hold of his laptop. He had 5 or 6 different girls that we worked with on there. Nude photos. Finally I confronted him about this stuff. He said the photos were old from before we were dating, which seemed plausible, and he had lied to cover up drinking as he knew he had a problem. He started coming home earlier and I thought things were getting better. 
A couple of weeks after I had the baby, one night he was asleep and his phone kept going off. I had a feeling. I picked it up and there were texts from an out of state number "are you there?"  "are you getting my texts?" and then a picture of her vagina. I texted her back and let her know that he didn't get them but his girlfriend (ex) did and if I were her I would get tested asap and I would leave this guy alone. She apologized and said she didn't know he was with someone and she hadn't seen him in over a year and they had never been physical. I was so devastated i didn't respond and foolishly didn't keep her number.
He said she was a former coworker whom he hadn't seen in a year and they had flirted before we dated, but it had never been more that that. He said he told her to never contact him again and he would change his number. I should have pushed it, made him call in front of me. We talked about it a couple more times he said he couldn't remember her name and a couple other things that seemed implausible. I mean, this girl just wakes up one day after a year and decides to send you explicit photos? With no encouragement from you? Right. Strike two.
Now our daughter is 9 months old. I've tried to let it go but I can't. Recently I went to get birth control and during the course of my exam was told i may have an infection. I am still awaiting test results. He seems unconcerned and says it is not an std but it has been a week and he has not gone to get tested yet. His work schedule is incompatible with an hour long drive at 8 am, but still. Worried what it might be, perhaps? I have stopped checking up on him as much and have gotten comfortable. He is now working in that same after hours bar he used to hang out at after work. I get the feeling he's keeping something from me and have wondered about drug use. He never has changed his number. I do not trust him. I don't know if he is an alcoholic, addict, cheater, or just a stressed out guy trying to do the best he can. I am going out of state for a couple weeks and during that time I should get these results. If it is something i will come back here, get my daughter, and take her to the other side of the country, where we will live with family. Because three strikes is enough.