Maintaining a long distance relationship as an expat in Portugal

I have been in an extra-ordinarily long distance relationship since 2010. In 2010, we studied together in Thailand, then, I moved to Norway in 2014, in 2017 I moved to Portugal for my doctoral studies. My gf lives in Manila.
Our relationship is strong and thriving, we absolutely trust each other. We meet once or twice a year in Asia or Eu, apart from that, we skype and video chat on facebook frequently, sometimes my gf calls me on my mobile phone not using the internet, because if I am away from home I prefer not to use inter-net.

Adjusting our different timing could be little issues, Manila is seven hours ahead of Portugal. So sleeping time in Manila is waking time for in Portugal. However, we still adjust our times according to our work schedule. Keeping our daily routine in mind, we do not pressure each other to talk on daily basis. But, we usually have quality talk either morning or in the evening. Above all, we have an excellent understanding between us, so except sporadic incidence,  we have maintained our relation successfully. But, I give credit to my gf for saving our relationship, she has been pro-active using different communication channels.

We are not married yet and do not have children. I sometimes go out with friends in Portugal and have been able to avoid physical temptations. I am not into too many late-night parties, however, sometimes I go to clubs with my female friends. Since my gf is absolutely faithful to me, thus there is no point thinking about other women. Interestingly, once my professor called my long-distance relationship 'toxic' because in normally circumstances such relationship won't survive. So, I consider lucky to have such a good partner.

Soon, I will invite her in Portugal.