15 year old being extremely careless with sex

I found out my son lost his virginity at 14. He's also being extremely careless with sex. Having unprotected sex with different types of people and caught an STD. He had a girlfriend but I found out from going through his phone that he was having sex with some male at the university near our home who was like 19 or 20 and he's doing so much careless stuff and also cheating. Luckily as far as we know he has not gotten anyone pregnant. He also hasn't caught anything that can't be cured... Yet. He can be very impulsive at times. His school has spoken to me about his behavior because he's having issues at school. They believe he has some type of emotional disturbance disorder. The school counselor thinks he should see the school psychologist because she does believe he has something like borderline personality disorder. His mood swings can get crazy. He goes 1 to 100 with little in-between. We could be fine. Then say the wrong thing and he's telling you to kill yourself. He can also go 1 to 100 with his self image. Things will be fine. Then he is telling you he hates himself and he wants to die and tries to self harm or something. It's extremely up and down with him and this affects his schooling too. Another reason his school counselor thinks it's some type of personality disorder like BPD is because they're caused by trauma and he has told the school psychologist about some traumatic events. My husband doesn't want him seeing the school counselor and is convinced he doesn't need it. They're just going to tell him he has some disorder to convince us to pay for medication the rest of his whole life. Which I told him if it is some type of personality disorder I'm pretty sure they can't be cured with medication anyway but he thinks he's just a boy who is going through puberty and everyone is making a mountain out of a mole hill. He's just a teenage boy full of testosterone and this is normal and will pass. My husband also isn't the one who has had to deal with having to physically fight him to get knives away from him because he's trying to harm himself. I think this is beyond "testosterone". My husband keeps saying he doesn't want him to see the school psychologist. Would I be awful to do this behind is back?