People slap curses on each other all the time. I'll tell you all I can in order to help you out for a bit. Once you step away from Neo-Pagan witchcraft magics, curses are a common phenomenon, unfortunately. They're a part of every indigenous system of magic.
The good news is they're often quite easy to lift, especially if the person who threw on you is a novice or a casual practitioner working within their native folk practices. The most experienced practitioner - the ones who could really "kill you dead" with the stuff - are the ones who rarely, if ever, use their skills. They're certainly not throwing on a high school student. So you don't have to worry that your ex is an experienced practitioner, since according to his actions he doesn't sound like one at all. It's not how it works. I believe that if someone throws curse that way he's just someone who does it, so it won't be too hard to lift.
I've got a few useful suggestions for you, choose to use them if you wish:
- Destroy and throw away anything ever given to you by the suspected person or anything ever touched by them. Make sure the suspected person does not have access to any of your stuff: your home, your personal effects such as used kleenex, drinking straws, hair, fingernail clippings, etc.
- Do a spiritual cleansing of your home. If you are too sick to do so, have your caretaker do it for you or at least have them add kosher salt and/or holy water to a bucket of lemon or pine-scented floorwash and pray while they do so. The 23 Psalm is a good one. You may find various methods of doing so, since I'm not going to make recipes or articles telling instructing step by step what to do, it's too easy.
- Take a series of cleansing baths. Bathe three times a week (mon, Wed, Fri) for three weeks with a spiritual cleansing product (Uncrossing, Jinx-Buster, a herb tea made from Hyssop, Purification, etc. I can give you a recipe if you desire).
- Follow this series of Uncrossig baths with a series of Portection or Blessing baths - three times a week for three weeks.
- Put up some sort of protection. If this person has constant access to your personal effects, you may wish to treat them regularly as well (bathing, using powders and oils, etc.). Use energetic types of protections: shields, wards, etc., use a protection spell: http://www.luckymojo.com/fierywall.html , and consider an apotropiac charm for protection as well.
... the good news is that crossed conditions are usually quite easy to resolve and respond readily to cleansing and protection work. Usually people only throw them once in heat of passion and do not continue with repeated attacks.
Curses manifest themselves in many ways and vary greatly depending on the culture. The main rule of thumb is that curses affect whichever system in your body is the weakest before the attack. You have asthma? Then the curse will affect your breathing. You're clumsy? Then the curse will manifest as an accident. You have high blood pressure? then the curse will affect your heart and circulatory system. This is just one more reason to stay healthy and seek regular medical care.
I always take concerns about curses seriuosly, because, as i said before, there are plenty of nasty people who use this stuff without much thought. The only time the validity of the suspicion put into question is if the "victim" suffers from certain kinds of untreated mental disorders: intrusive thoughts of attack and uncleanliness, obsessions and OCD behavior, paranoia, and the like. If i suspect mental illness is a factor, i will always ask a few tactfully-worded question inquiring into their medical past, whether they're taking (or not taking) any prescribed medication, etc.
If the victim is experiencing health concerns, i will not treat them for cursed conditions or prescribe spiritual work unless they've seen a doctor first. That is a lawsuit waiting to happen and is just common sense.
Don't worry about your kids. As soon as you take care of it and banish the negative energy, they should be fine. Energy won't always be of a problem in your place as long as you keep it peacful and banished. There is not need to accept the 'punishment' or the curse. Nobody deserves it... Hope it helps !