Hi there Aynat!
First off, I hope that you're having an amazing day today and hopefully feeling a little better about things with all the great advice!
I can relate in ways, i recently had broken up with my girlfriend of about 3 and a bit years. Although it was a very toxic relationship and went up and down constantly breaking up, getting back together, hooking up, the works really, it was time to let that ship sail for me.
Anyway! It seems as if your relationship was very steady, lasting seven years is definitely an achievement in terms of a relationship. You never meant "nothing" to him, you were together for a very long time and I can guarantee he would still have feelings for you regardless to what he is doing currently. Yes he does seem confused about his sexuality and has shattered your heart into a million pieces, but that does not mean that you can not be strong and move forward from this. This doesn't mean you have to go out and date or anything like that, because usually that seems to be the last thing people want to do when coming out of a long term relationship, that step can take months or even years to move on to. I feel as if for now, you should be selfish. Focus on your life, your goals, your ambitions. Find a new hobby, work out, connect with old friends, anything that will help you grow stronger in your mind and body.
I know the exact feeling of feeling like you are worthless after all that time, how could he just up and leave? The relationship may be over but you are not, YOU are strong and YOU can and will beat this!