Depression, sex and my relationship

Lowdown- Time together - 1 year and a half Mental health - bipolar (myself) PTSD (partner) Children - 4 year old to his X wife I have no children Work - Work together in 2 businesses I suffer from depression and am struggling so much with this relationship, any relationship really. Partly because I can't stand how my partner is with his child, he is very spoilt and as he is a part time dad he gets very stressed and overcompensates with everything to the point the kid eats crisps for breakfast! It makes me not want to be around the kid which is causing more problems I can see myself being really short with my partner all the time because he lies all the time about stupid things. Like he will say he is really good friends with someone but it turns out he's just spoke to them on Facebook. Lies are always based on ego and him looking good or knowing people. Everyone is his best friend until it suits him then he says he has no friends here. I am not interested in sex anymore and he's obviously really unhappy about that but I don't know what to do anymore. He sees me as the enemy and is so defensive. He's even said to me before that if I was a man he would of hit me by now. Obviously I'm no angel but I don't go out or drink and don't shout at him or get aggressive but ha makes out he's got it really bad and it's just wearing think. Also a few of his friends have recently told me he's a compulsive liar and owes people money. Again lied about his friends and his previous jobs etc. So hard to explain everything here but if anyone even slightly understands please help me.

are you bipolar 1 or 2 ? do you take any medication to stabilise any excesses in mood or behavior - and/or do you see a therapist ? are you always depressed or is it because you're on a "down" ? why does your parner suffer from ptsd ? has this anything to do with the fact he needs to "look good" (knowing people - having friends) ? is this why he lies basically ? is ge overcompensating with his child because he feels he's no good - in which case - has this anything to do with the mother of his child ? what relation are/were they having ? is she putting a lot of pressure on him to "perform" with the child and be "a good father" ? (which of course will only accentuate any ptsd) - apparently he does a number of things to "suit" him because he's in need of validation and encouragement : then of course you being upset because of him and the way he treats his child - is not going to arrange things necessarily - for him - for the child - for you - why are you no longer interested in sex : is it in sex - or sex with him ? often these ways of going about things / handling situations in a relationship go in cycles that become habitual when repeated often - then ingrained and repeat themselves automatically and then the relation of course can not really get better but only worse : at one point one has to exit the vicious cycle somehow - take a break - get away for a few days or what : something to break the addiction to repeating behaviors - oneself and together - you both might need to get some perspective and understand where you're each coming from and how that plays out in the relation - then come up with things to do to change behaviors, attitudes and ways of communicating - nobody can find a solution when stressed out and in depression start with considering concrete happenings in the moment - not things said or done yesterday : deal with situations in the now - so as to be able to bring forth objectivity on actual facts and then take it from there with concrete possible solutions - one step at the time - one day after the other sometimes things get in a knot : then one has to undo the knots one by one - and that may take some time :)