How much cardio a week before it starts to have an affect on muscles and their mass decreasing? Most times it will get rid of the fat first before the muscle right? If somevody is trying to increase muscle mass how much cardio should they do? Cause obviously cardio is still an essential part of anyone's program.

Not mine. When bulking I don't do any cardio for a couple of reasons:

1. I don't like it.
2. If I'm at the gym, I want to lift. Time's limited.
3. I'm working hard to get the calories I need and don't want to burn them by running.

I'll do it when I have to - and this is not to say there isn't a place for it depending on your goals - it's just not part of mine.

If your trying to gain muscle then you should be doing HIIT to minimize muscle loss and maximize fat loss.

Generally speaking ( for the average gym rat ) , IF your diet is in good shape - i.e you you take in an adequate amount of protein and you keep your carb based energy stores topped up, you pre-fuel properly and eat properly throughout the day ( and after workouts ) - you can do cardio 3-5 times a week without too much worry IMO. Doing 20-30 minutes of High Intensity Interval Training and / or 30 - 40 minutes of low / moderate intensity steady state ( SS ) cardio should be fine and not have a significant impact on muscle growth IMO.