What to do? what to DO!?

I'm pretty sure I got knocked up by a married man. My iud failed and at the clinic I was told after removing it there would be a chance I would miscarry. But here I sit two months later with a married man's kid growing in me. My boyfriend knows I am pregnant and knows about my indiscretion but I don't think he has put them together or is indenial about it. But I so badly wanted to believe that it is his. I don't know what to do.