first, i want to talk about your son. 14 is a TERRIBLE age. the hormones just begin to flow. parts of the body grow at different rates as other parts (mom, is my nose too big?). kids at this age are prone to "falling in love." i call it "falling n harmones." my grandkids hhated it when i said that. lol
add to this internal physical and psychological turmoil the trauma of a sepaation/divorce and the emotions associated with THAT and you have nitro getting mexed with glycerine. shaken, not stirred. your watch especially for changes in behavior. you mentioned that he had a hard time in school last yr. is this unusual? has he gotten a new set of friends? is he more secretive than a normal 14 yr old? don't be a drudge or a spy, but, if you love him, watch him closely. he could (not necessarily will) get mixed up with the underworld of drugs or gangs. he is a prime target for these bast*rds.
to counter any unwanted inppingement on him, give him a LOT of attention and see id your husband (ex?) can too. let him know that he's ok and has nothing to do with your breakup. you might also consider counceling (lady dragonfly, who is studying to be a coucelor, would undoubtedly agree with this sugestion).
now, for your other question. i call it the "heebee jeebies." it is common with bp (from my personal experience and from what i have read) as well as with several forms of mental illness. it isn't "normal" behavior, but it is not unusual given the probability of illness. the restlessness is a symptom of the disease, it is not a disease in and of itself. if he is not hurting hmself or anybody else, let him act it out. but be careful. one of the symptoms of mania is spending a lot of money that you may, or may not, have. if you can, keep an eye on the savings, checking, and credit card accounts. as with your son, you don't have to be beligerant or harsh. just keep an eye on things. when he's out, he is unsuperrvised and can get himeslf, and the family, in trouble.
my wife is a gem. when i get the heebee jiebies, she says, "ok. where are we going?" and off we'll go. once in england we went from london all the way to the gauer penninsula in wales! i have chronic debilitating back pain and take narcotics for the pain. my pain management dr put me on morphene yesterrday. god the pain was aweful!!!!!!!!!! i drive as little as possible. if i have an accident, it's automatically my fault beacause i'm taking narcotics and if i get stopped for any reason i can go to jail because i carry some with me at all times in case i get bad "breakthrough" pain. but that's my problem and a totally different story.
you asked how you deal with his acting out? disassociate yourself from his behavior. recognise that it's his illness and not yours. also get in close contact with your own emotions. again, therapy might help. you may love him, but right now his behavior is unacceptable and hurtful. see it for what it is ans act accordingly.
hope this helps.