i am not a scholar or very learned person but i personally feel that it is wise to conceal such things for the better specially when you have children.

Remembers,Shirk k baad,Allah k nazdeeq "talaq" ya separation of husband and wife sab se napasandida cheez hai.So insan ko apni capacity main rehtay huway mil baith kr hal nikalana chahiye aur aysi sitautions ko avoid kerna chaiye jis se un k taluq main kharabi paida honay ka khadsha ho.

Allah tala insan per us ki bisaat se ziyada bojh nahi daltay.Islam aik practical aur mukamal deen hai.Is per chal ker koi bhtak he nahi sakta.
Hum main boht si bashri kamzaoriyan hain.Jo k naik se naik insaan main bi zahir ho jati hain kisi na kisi mor per.Sirf paighamber masoom hotay hain.

Isi kamzori ko mad-e-nazar rakhtay howay Allah ka hukum hai k raaz ko faash na kia jaye jab tak ke koi boht bari kabahat na ho.Allah tala to maaf ker detay hain lekin insaan k dil main khalish rehti hai,woh kabhi bhul nahi sakta aur na he maaf kerta hai..

agar kisi insaan main koi aiab hai to ussay shaadi se pehlay zahir kerna chahiye jaisay k koi physical ya mental abnormality ya koi pehlay se married hai etc etc ...iss ko chupana skhat gunah hai.
Lekin agar kisi ka kisi k saath affair tha past main to yeh boht buri baat to hai per iss ko aib consider nhi kiya ja sakta specially jab us se koi kharabi paida na hui ho ya aysa koi khatara ho future main.Khass tor per jab woh ALLAH se maafi maang le.

Hum sab gunah kertay hain aur koi aik mard ya aurat aysa nahi k woh gunaah se pak ho.to humain yeh haq hasil nahi k kisi k gunaah ko kuraid kr us ko sharminda kiya jaye.
aur agar husband ya wife ko shaadi k baad iss type ki baat maloom ho to pehlay aram se baith kr doosray ka nuqta nazar jan'nay ki koshish karain.
ho sakta hai woh sachay dil se maafi mang chuka ho.us k past k liye,future ko barbaad kerna ki zaroorat nahi.haan,agar shaadi k baad bhi woh buraiyan zahir hoon to separation he hal hai.

jab koi insaan sachay dil se maafi mang leta hai yo woh pure ho jata hai.is liye agar koi aurat ya mard sirf aap ko kho denay k dar se aysa jhoot bolay jis ka future main koi khaas effect na perta ho,to i think it is permissible.Jiasa k yahan mufti sahab ne bhi bataya hai k apnay relation ko bachanay k liye jhoot bhi bolna peray to gunaah nahi(in extreme conditions).

Har insaan ki fitri khuwahish hoti hai k us ki wife ya husband k liye woh sab se pehlay aur mehboob ho to agar zojain mutual understanding se aik doosray k saath apna past share kerna chahain to koi burai nahi but us k baad baat wahin kahtam ho jani chaiye na k zindagi bhar usi lakeer ko peet'tay rahain.aur yaad rakhain...
khamoshi main he hikmat hai.

aap agar logon k past ki investigation kernay start ho jayen gay ya boht perfect insaan dhoondhnay ki justaju karain ge to aysa namumkin hai.
isi liye apnay ander ki buraiyon ko dekhtay huway doosray k gunahoon ko maaf ker dena afzal amal hai.

Regards.

__________________
Work until your idols become your rivals.