1 year and already a mess

I have been with my husband for 10 years we got married 1/28/17 and I suffered a miscarriage. He kind of grew away from me but not completely I suppose bc I take care of everything, i.e. the bread winner. we started fertility treatments in august and I got pregnant again in Sept well I recently found out that the weekend I went to visit my best friend in DC to do my trigger shot he slept with someone else and she got pregnant 2 days prior to my iui. apparently they have been dealing with each other since April. I miscarried Oct 28 and she may or may not still be pregnant but he wants to start another cycle I don't know if I can mentally handle someone else having his first child after my 4 miscarriages. and he told me he was planning on leaving me but he was playing along bc he had no where to go. I don't know what to do.