Martial Arts Sparring

Ok so i’ve been doing taekwondo for about two and a half years now, im four ranks (or a year and a bit) off black belt. i do love taekwondo, its great fun and sparring is most enjoyable. its not a mcdojo as we are trained by a korean man with a 8th degree black belt in both WTF stlye taekwondo and Hapkido. I love the people and my master at the dojang and really wanted to get black belt.

but at the same time, i love all martial arts and want to expand my horizons to others. i also love mixed martial arts and ufc etc etc and often have full contact mma matches in the backyard (lol). so I recently discovered that then next town over has an mma gym. it has classes in mauy thai, kickboxing, BJJ and strength and fitness (which i am very interested in as i have alot of trouble putting on any weight and/or muscle). ontop of that the mma gym costs 25 a week with unlimited access (upto 15 classes a week, not to mention you can probobaly use the gym anytime as long as its open between classes). which is WAY better compared to taekwondo’s per lesson once a week with no real facilities (we do it in a school hall/ indoor b-ball court) not to mention gradings cost 50 each and u need to pay 55 for insurance once a year.

so my dilema is i cant afford a week to do mma AND taekwondo. yet i still do like taekwondo and dont want to "betray" my master and dojang. but mma is so much cheaper and teaches so much more.. WHAT SHOULD I DO??

and plz no answers telling me how "unneffective" tkd is etc etc.