The others all mentioned perceptive observations... . What he did is definitely not something to be explained away or minimized as 'no big deal'... . His behaviors showed he put you at risk literally, time to put yourself and the children first and figure out what that means... . Start documenting things in case you do end up seeking court action to resolve custody, support and division of marital assets and debts... . This had a stunning impact on you, you have a right to let this sink in and give you time to figure out how you want to handle this... .
Some things were alluded to - his dangerous behavior with repeated unprotected sex. What that means for you is that (1) you have a right to decide to end or at least suspend intimacy based on both the lost trust and real health risks he exposed you to and (2) you ought to get tested for STDs and repeat them again as the doctors recommend in order to confirm nothing surfaces later.
It is so hard to look at him the same, and even harder not to let this affect my self esteem... .
Don't let him twist this around on you. Don't feel guilted and don't let him make you feel guilted, this is his behavior, his consequences, not your fault at all.
Lastly, for many people this behavior - infidelity, and repeated at that - is a "deal-breaker". He's making you feel you shouldn't feel how a normal person would feel, betrayed and sabotaged. However, you had trusted him and did not expect this, he broke that trust. It is very unlikely he will be sufficiently change and regain your trust. What that means is you have a right to reconsider everything including the relationship, the marriage. Seriously.