Pregnant and emotionally abused

I’m 14 weeks pregnant, my boyfriend of 8 years cheated on me a few months s ago, I forgave him, the last few weeks he has been saying he’s getting checked for STIs because he thinks I’ve slept with someone else,,, I definitely have not!! He says hes not having sex with me untill he’s been checked, every night is the same, I can’t take it, how do I text him and say I’ve had enough and I don’t want it anymore?? I just keep taking him back because I love him more than anything, I’m scared to lose him for good, I know he’s cheating he just keeps lying to me!! He swears on his moms life, on his kids life and still lies, that bits childish but I don’t care,, why can’t he just tell me the truth!! I’m getting checked out for STIs just incase