How long do I keep fighting..

How long do I keep fighting for our marriage? My husband doesn't leave me but any time I bring up an issue he tells me I'm free to go if I am not happy, or that he keeps telling me to leave and if I'm not happy then it's my fault for staying. I feel like I have to beg and beg for any kind of sex, and then it's like he doesn't enjoy it at all. We have had problems with him cheating in the past and he has admitted he has a porn addiction (in our relationship we both agreed that we would not watch porn). I forgive him over and over but I feel like a joke. I look nothing like the women that he enjoys watching and I've become so insecure about my body, my personality, everything.. I just need advice, thanks for reading this.

*Edit* We've only been married around 5 months, and dated 3 years before we got married. I buy lingerie and new perfumes and try to be sexy and spontaneous and he just blows it off and seems uninterested. We are each others only sexual partner and I'm worried that now he wishes he would have experienced more before we got married.

*When I said he cheated, I meant he was taking women out to lunch behind my back, texting them calling them names that he calls me and hiding messages, buying them things, things like that. He never made it to having sex with any of them. Sorry I didn't make that clear at first.