Well first of all... I'm a Marine meaning I am in the business of following orders. With that being said, if they say I have to fight next to a woman there is nothing I can do about it as I do not make policy I just enforce it as a leader of Marines.
My only thought on this subject is this... The Marine Corps has been effective in completing the mission for 237 years. Is implementing this policy going to aid us in completing the mission better? If not and the only reason for this is to make a small percent (about 13% of the USMC is women) feel better then they are doing this for the wrong reasons.
Any woman Marine who says it is for promotion opportunities should know better because they already know combat has a miniscule impact on promotions. So if this is for bragging rights or just to make a person "Feel" like something then all it is, is a feel good policy which it is a bad decision. This is the difference between someone making it home to their family and not a social experiment.
The last thing I am going to say about it as a combat vet of both Iraq and Afghanistan to the women who are pushing for this is... Be very careful what you wish for. There is nothing glorious about combat. Knowing somone is trying to shoot you to end your life is not a fun feeling or something that makes you more proud to be you. Our responsibility is to defend the nation and, at times, take lives... This is not to make you feel like one of the boys.