Actually, I think you are doing your own pretty good job at psychoanalysing your own psychological 'condition' - as it were.
The thing is, we want to love our parents, we as children growing into adulthood desire that our parents are those people that would never think of failing or disappointing us. But alas, that's not reality for many of us and what we desire - from that heart that still contains the heart of that child still within us - and what we would much rather have as true.
We feel terribly betrayed by the 'sins' of our parents. They are meant to be our role-models, meant to represent all the good things of integrity. I think that some people should never become parents, but life being what it is... A parent ideally, IMO, should be someone who believes they are emotionally capable enough to see themselves raising a child to healthy psychological adulthood. In an ideal world, eh?
Your mother sounds like she's borderline personality disordered. Given to rages and emotional roller-coastering - anything to enlarge her emotions. It's a tragic situation that the person we have believed and trusted in to nurture us is herself or himself a very wounded and psychologically damaged individual.
You're a grown man now and maybe you can finally begin to put the past away and see her in that respect that I have described above. You're also very hurt for your dad's sake and maybe you see your mother's infidelity as a betrayal on the family for not only was she unfaithful to your dad but to you too. That trust was betrayed and the wound has cut deep.
You don't want the girl you end up with to be made to feel insecure by controlling/jealous behaviour from you. Consciously you know that your gf is not your mother. But it's that fear that makes you want to check up on her to make sure that she is not going to end up like her ( your mother).
I would suggest practising further self-awareness. Don't allow yourself to unwittingly fall for a girl that is like your mother (maybe ask your dad what your mother was like, personality wise, when they were dating?). A fear of marrying a girl that might end up like your mother is like a subconscious desire to do just that so you can 'fix' the past by attempting to change your mother (who your gf would substitute for).
Somehow or other you will need to let the past go. Right now you are feeling the pain and I really think we need to feel that pain - that hurt - so we can finally get past it.
Like Pmother says above, you can only be responsible for your own moral code. You place morality and ethics highly, and the world needs people that do, but you cannot change the way people are, they will either 1. make their own mistakes and learn from them or 2. make their own mistakes and not learn from them.
I would therefore suggest that you seek friendships of people that are of the first category, and when your friends do make mistakes, just realise that we are all capable of them and forgive them and yourself. You have the choice here so it's not about predestination about the past to do with your mother and history repeating. Now you know how you really feel inside, you can ensure that history does and will not repeat itself.
Keep believing in the power of love that is less of the emotional kind and is more the 'act' kind (emotions can be transient) and remember to laugh often.
Good luck, mate!