Need advice

Hi Ladies I'm currently 15weeks pregnant and I'm super excited but I'm not happy in my relationship. I've been dating my boyfriend for almost 2yrs but I've known him for a lifetime. Our relationship hasn't always been great but we were getting better but around the time we found i was pregnant he left to work out of town for 6mos. I've been feeling very alone and he's always partying so I'm constantly worrying about what hes doing and who he is with. I don't know if it's the pregnancy that's making me feel this way or if I truly just don't want him anymore. I find myself crying alot because I don't feel the closeness. Should I break up with him or is this just my hormones?