Help!

Me and this guy have being seeing each other. This guy came with a lot of extra baggage. He lied about having kids( he actually has one that should be here anyday). We parted ways for a little bit but we always managed to keep in touch. on our break he had sex with another women. I met another guy that I liked and we actually became sexually active with each other. The thing is I still love the other man and I think I might be pregnant by the new man. I don't want the old guy to leave me alone completely and I know for sure that he will if he finds this out. What should I do??? Help. Please!!!