I am so sorry
I do know how you're feeling because my OH has a cheating problem. Many people don't understand why, but I've decided to stay with OH and we've decided to try to work it out. It's so different when it's actually happening to you as opposed to what you think you'd theoretically do if someone cheated on you. I think most people think, in theory, that if their man cheated on them, they'd be super strong and tell him to leave or just leave themselves, as if it is really easy. It's actually more complicated than that sometimes when you're in the situation. For instance, in mine, I'm 8,000 miles away from friends and family and I'm living in a totally different country with a totally different culture. That alone was enough to make me want to work it out with him because if I called it off and went back home, that's quite a lot of money and distance if I changed my mind. Now that I'm pregnant, I want to work it out with him even more.
Of course, it is an intensely personal decision that you must make for yourself whether or not you want to try to work through it. You have to look at what is best for you and for the baby at this stage. If that is going and finding a friend to put you up for a while as you figure out what to do next, as difficult as it is, try to work towards making that happen. If it's dragging your boyfriend to some type of mediator (like I did, at our church) or counselor, do that. In my opinion, not EVERY cheater is always a cheater. I really have seen it happen where some guy or girl who was totally promiscuous suddenly snaps out of it and settles down. It takes a bit of time and the person HAS to be willing to change. It's like quitting smoking - you can't MAKE someone quit smoking. It would work in the short term but in the long run, if it wasn't their decision, they'd just go right back to smoking, and I think that's what happens a lot of the time with cheating and that's why there's that saying "once a cheater always a cheater." You can't ENFORCE on someone that they must change. You can only have a candid conversation with him and ask him whether or not he wants to change. If he wants to, then you at least have something to work with there. If he doesn't want to or doesn't see how he can, then there's not much there to work with. That's the key that helped me decide I wanted to stay and work it out.
There's the matter of making sure your boyfriend acknowledges that it is not just you any longer, it is you and BABY, to take into consideration with actions like his. He said he only kissed (which is ATROCIOUS enough) but if he were to ever do more, and then have sexual relations with you again, he'd be putting you AND the baby at risk for STI's. This is a conversation I had with my OH once I discovered I am pregnant. Your boyfriend needs to hear this because it's not something that might occur to him. You have to make sure you protect yourself and your baby's health and well-being, so this is a talk that really needs to be had. Hopefully kissing is all that happened and will never repeat, but it's still worth it to have this talk. (Also when I say hopefully kissing is all that happened I do recognize how devastating kissing is, I'm just saying above and beyond kissing, like sexual encounter that could expose you all to STI's.)
Sorry this is getting so long, I just know how much this situation sucks. It is not easy. It makes you feel so isolated and alone and hurt and like you have no where to go. My best advice would be to get somewhere that you can feel safe and relax and get your mind off of it because you can't really come to rational conclusions when you're in an irrational situation that is making you upset, because it will just cloud your judgement. Also it's important for you to relax for baby's sake because high stress is not good for your baby. So it's really, really, really, really important that you find a place to go take a walk, go take a bath, go watch a movie, go see a friend, do something that takes your mind off of the situation or at least makes you LESS UPSET, because only then will you be able to look at the situation, weigh the pro's and con's, and come up with a constructive plan that will help you survive better.
I am so sorry this happened. Communication solves more problems than you can shake a stick at, it really does. Even when it feels like you want to communicate LESS, you should communicate MORE. Just make sure that you try to stay calm and level-headed when you talk because as tempting as it will be to scream and cry at your boyfriend, a) that's not going to help anything and b) again, that is going to harm your baby. I hope that you are able to come to a decision in your own mind and from that point you'll be able to figure out a clear path of action.
If you need anything, feel free to PM me!