If you believe him, there is no reason why you can't try a therapist to see if you and he can work things out. I believe it's better to try than to turn your back. If this isn't the first time, then get out while you can, but if it is the first time, maybe it's an error and maybe you can correct it. Be ready to tell it all, the whole truth about how you feel and how he made you feel.
Some insurance companies cover therapist visits and can recommend a good one in your area. If not for marriage help, but for yourself. Trust me take care of it now, or you'll do like me and go through it 40 years later.