Cheating an affair it cant be is it?

Hi, My husband and i are together 5 years .We dont have kids yet because kids scare me right now and im afraid of doctors which is bad cause my husband wants children now and i cant because i really am not ready he is 40 im 29.next to my problem my husband was divorced he was married to a thai woman he is not thai he is dutch,they got a divorce and he had a child with her he dosent really see the kid but pays in the financial part..since 5 months ago a thai family live near us infact right next door and theres a thai woman there she isnt married and i find my husband out a lot in the garden and in fact he seems to be coming home from work really late sometimes 3 in the morning he is an accountant ,im worried he could be having an affair as he is into thai women becuase he is too friendly with her and dosent spend much time at home or with me i feel i am losing him.i asked him is anything going on and he says he is doing overtime am i blind? i dont know is he lying or not why is he having so many late nights what do i do am i just being silly ? HELP!