Is your boyfriend in therapy ? If not he should be.

Seems all the people he was involved with was before you and him got together, other than him not disclosing that it was a few months not a year .... so I dont really see any "lies" here,,,, a few omissions sure.... You have been together only 4-6 weeks , this is very very early in a relationship.

Now that you know more ... are you going to be able to offer support and give him time to hopefully work out what happened in his past with a Therapist?