It's a tough situation. I work at sea, but thankfully not for 9 months at a time.
I have to admit it was hard leaving my family behind, especially when they were in the Philippines. I'm not sure how I'd cope if I found out there was cheating going on.

Of many of the Filipino colleagues I worked with at sea/overseas in Filipino+Filipina relationships who were away for seriously long periods of time it seemed that quite a few cheated, or were cheated on by their spouse.

Seaman tend to become quite detached, and housewives can become quite lonely.

If you want to discuss anything and talk it over, feel free to PM me.