Think he gave me an sti

So I've only ever been with my boyfriend, we've been together years. Have two kids together. He took a job in another town that meant that he was away for 6 months and visiting now and then. I had been getting period like cramps when I wasn't on my period, then I felt weird bumps around my vagina so I went to get checked out. Got my results back that I have Chlamydia and genital warts. My boyfriend then accused me of cheating! I haven't been with anyone else ever so it's obvious He has played away. He will not admit that he has been unfaithful, where do we go from here?