I want people's input on the thoughts I have put here.

You're on a rollercoaster. You're right and you're right: Life is short, what's the point of staying angry, forgive and move forward, rebuild... and... he betrayed you, he hurt you, destroyed trust. So, since you can't have both and move forward, choose one.

Or am I still reacting from hurt and anger?

A good question always. You know the answer, look inside you and think of where your feelings come from and understand them and why you have them, and you can then deal with them better.

Part of me recognises that he put some effort into all of this. But part of me has just been left really cold - he put really little thought into the gifts themselves. Even the things he wrote in the card was so lukewarm that it was a slight shock. I guess I wanted gestures that showed that he cared for me and valued me and appreciated all that I have done over the past few months.

It's the expectations you had that weren't realized that now makes you feel empty. Turn off the expectations and see the positives, as little and tiny as they are, as Michele writes, they are still positives. And unlike unrealized expectations, they are real.

But then also if H is still attached to ow, then I wonder why I am doing all this. If she makes him really happy, and he is in love with her, then should I not just wish him well and leave them to establish their life together? Why do I want to break them up?

Uh oh, a philosophical question. The question is, if you love H, and want more than anything for H to be happy, then why not let him go since he seems to be in love and happy with OW, right? My answer to that would be, theoretically, that sounds right on paper, the problem in real life though is that he may appear to be happy, but it may be just an appearance or imagined or fleeting even if it's genuine. It may not be the best thing for him long term that genuinely brings happiness with it. How do you know for sure that person shouldn't be you in the end? Aren't you the one that's maturing from what you're going through and learning better what is needed to sustain a great relationship and are you not becoming a more compassionate, understanding, wise, patient and loving person? Aren't you also the one who is now gaining a better understanding of what it means to love your H?

just wondering if this is not a chance for me to leave a relationship that has no hope of getting better?

Maybe... and you will know it when that's the case, because you will be feeling like that and only like that for some time and it will become obvious to you and in that day you'll probably find you haven't been thinking about H for some time and it will feel nice and right, IMO.