Where would you draw the line?

I've been seeing a guy for about 8 months. He has periodically used Grindr since the beginning but stopped in the past few. Now he is abroad and still using the app. I don't think it's going to work if he continues to do this, but I do understand he is essentially "alone" in an unfamiliar country.It's never really been "okay" with me, but I stopped dwelling on it when he told me the purpose of his use. I don't know if I buy it, or if I'm being naive, but I generally trust him.But seeing him online constantly while overseas is just sending a very uncomfortable message and basically reiterates the doubts I had in the beginning: that he is not "the one". I need advice, preferably advice that isn't one-sided. I understand that not every gay man uses that app for sex, but it's only natural that it would create doubt.