My partner and I have been together five years. Long story short a year ago I found out about his unhealthy habit (at the start of our relationship I was quite "open minded" about porn - until it started to affect our relationship) and all of the lying (well most of it). We stayed together I forgave him & he promised it was no longer an issue, had a brief stint of therapy. It turns out I had no idea how bad it was even "when it all came out". Worst thing is that our relationship has been mostly fantastic since then & he proposed to me. I was over the moon & not 5wks later I discovered him wanking at the computer, he says he was able to separate it so completely from our relationship but I don't know if I can even accept that. He knew it was not okay, he knew he had issues that he had not been completely honest with me about and he failed to come and speak to me when they returned. I thought we were so close and could share everything - even difficult things. Now all our family and friends are expecting a wedding date to be set in the next couple of weeks (we were days away from booking the venue when I found out). My engagement ring looks meaningless to me, before it was the most precious thing and made me so happy. He lied to me about other stuff as well, little things but just so that he would not have to face any criticism or conflict of interest - he wanted to do what he wanted in spite of our relationship, despite me being open and generous to him having his own time and own interests. I'm so confused and hurt, he was my best friend. He is now in therapy in earnest - he knows it requires deep psychological change. I know I cannot change him but I believe it's possible for people to change themselves. He's always hidden problems from himself and others as a way of coping, avoiding intimacy & keeping part of himself separate in order to not feel vulnerable. Do I just cut my losses and leave? I hate that he has made this decision so much more binary by us getting engaged.