What is to be done if husband is behaving suspiciously?

I am married since 2yrs,after1yr of marriage husband got transferred to Bangalore,we r well connected but on August without informing me my husband went to guahati for a brothers marriage function for 12hours as he said,cause within this period I didn't contact him as bcoz I am seriously ill due to arthritis,I found pictures of him in Facebook,I contacted my in-laws they said they wont help me my husband took decision by himself, and they also not agreed at the time of marriage so I should not talk to them about any problems regarding my husband if I face problem. That's their reply to me,now my husband very frequent don't receive my call where he is going or doing what I don't know, cause he don't receive calls,only when he is OK to talk to me then only he receives my call. I lost my job due to illness for 1and 1/2 yr,so I am not able to go Bangalore to search for him what he is doing or not,my mother is widow we r helpless.but I can't waste my life prevailing this problem, I want a s