therapy after infidelity

My boyfriend (once fiancé) and I just had our first therapy session after I busted him cheating on me 2/13/17! Three days later I find out I'm 4.2 weeks pregnant. It has left me to consider abortion or adoption. He wants the baby 💯 but I'm fearful of ending up a single mom for a second time. He also has a past drug addiction problem that leaves me in fear of him returning to prison.