In general, you have 3 options:
1- if you love him and he loves u still in a way and cant live without him, you should live with it, continue life as normal
2- if you think u can afford and ur feelings have changed towards him and want to survive ur marriage for many reasons and kids sake, you can continue and manage a side relation urself till ur kids have grown up
3- if you can not afford and handle the issue anymore and dont want to live wth him anymore and you are able to manage yourself separately, then go for separation or divorce.

of course these are general guidelines to help you in a way but there are many details to be known to take the right decision.
if you need more assisstance I will be glad to help you as I know many people faced similar situations. you can send me private message

Hi if you are a bi woman living in Beirut please contact me