Don't ask directly. Asking directly will build trust issues and of course, you don't want it. So what will you do?.
Just talk normally the way you talk every day. Observe your partner's mood. If everything is good and the conversation is smooth just ask with putting some butter on it like- If you don't mind may I ask you something, my love? I was feeling insecure about that (your doubt) see you know how much I love you and I'm so far away from you so these things make me insecure.
Trust me your partner will comfort you with too many explanations and your doubt will be clear
If your partner love's you it doesn't mean he or she trusts you as well. Building Trust takes time. So there will be times when you will demand something and your partner will say NO. This is the best time to gain trust, be understanding, don't force, don't be angry. Being forceful or angry will make you lose their trust. so first gain your partner's trust and then demand anything you want. Your partner will surely full fill your demands.
Don't stop your partner from hanging around. Don't stop your partner from posting pics. Don't stop your partner from making new friends. Don't ask your partner to block someone. Don't ask your partner to stop something he or she was doing before you came into life.
These things will irritate your partner and you will end up losing them.
Always remember your partner had a life before you came in, and you are not the only one in your partner's life there are friends, family, work, so many things. So respect that and keep loving them. Be expressive about what you feel, tell your partner every single thing you feel bad and good in a loving way.
Your partner will take care of your likes and dislikes once the bond becomes strong. Be Patient.
There are some simple things that you must not do like- Being controlling, Being demanding, Always having doubtsYou can control, You can demand, You can doubt but, There is a way of doing everything. Follow the rules written in the article and make your relationship work.