My ex is pregnant and I think it's mine, what should I do?

I just recently found out that my ex girlfriend is pregnant, she is showing already but claims she is only about 4 weeks pregnant and hasn't gone to the docters... Can you show this early or would it resemble more abouts 8 weeks which would make her expecting baby mine... see also she is claiming it's her new boyfriend's... if I found out that it is in the period of when we were having intercourse, what should I do? should I tell her or should I just let them be? See I still love her but her new boyfriend is abusive and seems to hurt her, from what she has told me... but she still love's him I think, all I want is 4 her to b could I please get advise on what to do?

Well technically she could be showing already, but she really shouldn't as the only thing happening in her body right now (if it is only 4 weeks) is the developement of all of the baby's major organs, it isn't until the second trimester that the baby itself actually starts growing. If she is showing she is probably just eating a lot as most newly pregnant women develope major appetites. But if she is showing the chances are she is more than 4 weeks pregnant.
What you could do is ask her again how far along she is and then just time along with the pregnancy. If it happens that she was 8 weeks or so and you feel that the baby could be yours you could demand a paternity test, but that's getting into all kinds of legal battles. Just stick through it man...but make sure she is safe, if this guy is still abusing her during her pergnancy he could end up killing or severly hurting the baby, and that's not good.