This plus speaking as a guy whos been where you are, Its all about how you pick them, I had a terrible habbit of picking up easy girls and expecting them to change and be loyal to me.

Not sure Age has anything to do with maturity.

I would guess its the type of women you are getting involved with. Try someone with a personality of her own rather than a mish mash of what she thinks she should act like based on Movies and Tv.

If shes saying one thing and meaning another it means shes not comfortable being honest with you, an shes likely testing you to give herself an excuse to leave you without feeling like the bad guy because you didnt do anything wrong.

Stop meeting girls in clubs, start making friends with girls and find one your compatible with, even if shes not drop dead in a mini skirt.

Its a greater betrayal from a partner than a friend.

Im not saying you high five the guy, but i could at least forgive them for it.

Partner, nope never, its their duty not to break your trust, not the person they're sleeping with.

Just my opinion, but does it really matter? if you enjoy spending time with him and he makes you happy, does it matter if you have to open your own doors?

If hes not making you happy enough to let go of the fact hes not traditionally romantic then i would suggest moving on. Because its not a lack of flowers thats making you want to change him

Nope, neither forgive nor forget the partner, forgive the friend but never forget.

Chances are if they will cheat on you with a friend, they have an will cheat on you with strangers.

As long as your friend is upfront and honest about it all and wants to be forgiven sure.