Is it weak minded? I don't think so. You're hurt, for sure and you've a lot to work out in your mind.

Rome was not built in a day, but I really do think that you will start to change your ways and also let go of the pain. Forgive me for saying, but your mum has kind of controlled you all your life - and it will take time to get used to the situation now. If nothing else, I should imagine that you'll just tire of being upset and being in a situation that you can't really change. It may be then that you accept what has happened 100% and start to just get on with your own life. I also think that perhaps when the baby comes along that you'll have your hands so full that you'll have less time to keep mulling this over.

I do hope tho that you stop punishing yourself, and also let go of the resentment you hold for your hubby. Make yourselves a tight little unit if you can - he and the children are your family now and should be a priority.

Hugs

Edited: I know you are humming over therapy, but I really cannot recommend it enough for you. Not only will they listen without judgement, they can teach you wonderful ways of changing your thinking pattern. I think even a few sessions will help you if he/she is good at their job.