The way to beat players who play strong openers is to play a strong opener yourself, but not necessarily all-in aggressive. If you want to get to the late game you enjoy you must get better at the early game. Harass the other guy early, scout their build, make sure you're building counters to what the other player is playing. Defend well. Deny their economy here and there. Inevitably crush them with nukes and capital ships after 30 minutes of solid fundamentals.
(Starcraft is still a lot of fun and I'd encourage you to get back in to RTS playing)