Hey Lucy, there are some people that just can't handle antidepressants so their bodies react negatively to them. I don't know if you have had a firm diagnosis of depression or not but it almost sounds as if perhaps your situation is what is bringing about the problems. Thus it would be Situational Depression (text book) so, antidepressants are not prescribed to cover up or mask the problems they are given so the person can come up from the depressive state enough in-order for them to be able to deal with what is going on in their lives. Hopefully.
Please do correct me if I am wrong here but, it almost seems as if you are feeling that your husband is taking advantage of you and your financial situation. Or perhaps you miss how things were in the beginning? But most usually people change or we don't really see who the "real" person is when you date for a short period of time or it is a rebound relationship.
Just from what you have posted here...My suggestion would be to talk to him regarding your thoughts, feelings and concerns. If he isn't responsive or doesn't step up like you are wanting him to then maybe you might want to look into a legal separation or something along these lines. You need to set up some safe guards against your account and any assets you have. Especially if he is already telling you that he will take half of everything you have if you leave. It sounds as if your the one paying the bills and taking care of the household expenses, since you said that he spends all his money flying to see his kids, so that would tell me that he is the one that needs to go...not you. Hold your own and don't let him bully you. You have many factors on your side here all you have to do is consult with an attorney and see what your options are, if your at that point.
I also recommend just for your own mental health for you to get back into your own fitness program...you don't need him to do these things with you. Maybe try joining a gym or something of this nature...the exercise will do wonders for your depression and self esteem.
Regardless of what you do we are always here for you. Take care and keep posting