My husband likes to tell his friends bad things of me

I am 30 years Asian and my husband is 45 years Caucasian, we have been together for 3 years and have 1,5 years lovely son. Just to let you know that I have been told as an interesting person, sexy and still in shape even after having a baby. Basically we have a lot of problem in our relationship and I feel our relationship is even worse time after time. The first problem I found out in our relationship is my husband doesn’t show any respect to me, when we go out somewhere together he always looks at interesting slim women and even turned his face to let his sight to see where the women go and he wouldn’t care even when he is with me. Honestly I feel down when he does it to me and when I complain he said that’s normal, every man in this world would do the same as him. The 2nd problem, yeah sometimes when he is happy with me he tells his friends how fantastic I am but when it comes into argument he’s straight away telling his friends how horrible I am and he wouldn’t care telling them all bad things about me. One day I told him he shouldn’t do it because however I am his wife and in my belief we shouldn’t tell everybody about our relationship problem or bad things about our partner, and his answer was its normal for western to do that. So I don’t know what is right? But to me it is not right to let our relationship problem becomes public consumption. The 3rd problem, he doesn’t understand what woman needs. Only in the first 3 months we are together our sex life was so fantastic but then it’s almost nothing happens, ok let me say sometimes we have sex only once in one or two months. And when I talked about our sex life with him he said he rather go to the gym and doing exercise than to make love. He often stays late at night to sit in front of computer and visiting porn site, to me that’s not a problem. But one night when I awoke up and I got shock to see him wanked himself while he was watching porn DVD. And then I told him off, that what he did is too much… watching porn nearly every night and no sex life in relationship. And his answer no any western woman would get upset about what he’s doing. So in this forum I would like you to tell me what you think about our problem and what should I do. Have I to save our relationship or no worth to do it?