Olá, @davinsclin and welcome 
You’ll be FINE. Like in any other country, there is homophobia, but the Portuguese are generally mild-mannered and prefer to mind their own business regardless of their personal thoughts, and I’ll risk saying this is true no matter where in the country you go (there are always exceptions, but that applies to the whole world). It’s especially true in the bigger cities or more touristy areas. Some people may stare if they suspect you are gay, many out of simple curiosity. People can also be very gossipy, but they generally won’t bother you or reject you just for your sexuality. As a foreigner, you probably get even more of a pass to be/do whatever, within reason, because for the locals, you’re already “different” anyway. PDA beyond holding hands or the occasional quick peck is not appreciated (for any gender combination); otherwise, I wouldn’t worry about moving to Portugal.
For whatever’s worth:
Everything I said above is a fairly accurate (I hope!) surface-level description of what to expect in your case. The reality for someone growing up here and dealing with potentially very conservative families and communities all around them may or may not be very different, so I don’t want to generalize too much.