help please

so about 10 months ago I saw gay porn on my boyfriends phone and honestly we ended up getting past it even though that was very hard for me to understand and get over but I do love him and want to be with him. so we got past that... but then the other day we were both at work and he texted me a screenshot of texts with his brother and I look in the corner and see "back to grindr" which is an app with ALL guys.. to talk meet up send pics etc. he said he was downloading a different app and saw it and downloaded it and it was just that one time at work... Honestly I don't think he's gay but he has some interest in the same text. and use how to move on. I'm 30 weeks pregnant this Friday and I honestly thought we were really happy and ready to start a family. my mind isn't even allowing me to get that upset over this because I know the stress is bad for the baby. I also worked the past 7 days so I've been busy and haven't had time to think much. today I'm off and I'm wondering what the hell I should be doing... is leaving him really what you'd do? I just need help. we live together and have shared our whole lives together. we spend EVERYDAY together like anywhere he goes, I go. we are VERY close. he's my everything but I can't keep letting myself get walked on... I also don't know if I could leave him plus I know I can't raise a baby on my own. idk how to move forward and how to not worry about what he's doing... he cried to me saying he won't do it again and he has a family now etc but he also knew that when he did what he did... idk any help please. if you're going to be rude then don't bother commenting. I really don't need that right now.